Name: Determination of the Excitation and Coupling Rates Between Light Emitters and Surface Plasmon Polaritons (Video) | JoVE Journal
Uploaded: 2018-07-21T12:30:00.000+00:00
Duration: 7 min 39 s
Description: Learn to measure excitation and coupling rates between light emitters and surface plasmon polaritons using angle-resolved reflectivity and photoluminescence spectroscopy. This accessible method enables fluorescence enhancement studies without complex time-resolved instrumentation.

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5 minutes

This research was supported by the Chinese University of Hong Kong through the Direct Grants 4053077 and 4441179, RGC Competitive Earmarked Research Grants, 402812 and 14304314, and Area of Excellence AoE/P-02/12.

1. Setup of Interference Lithography
NOTE: Interference lithography is used to fabricate the periodic arrays12. The schematic setup, as is shown in Figure 1, is built up as follows:
<ol>
	<li>Focus the 325 nm laser from a HeCd multimode laser to a 13X UV objective lens and pass it through a 50 μm pinhole based spatial filter for mode cleaning.</li>
	<li>Place two 2.5 cm diameter irises 30 cm apart to further filter the central region of the diverging light. After the second iris, the beam diameter equals 2.5 cm and increases very slowly with distance, which is &lt; 3 cm at 1 m distance from the second iris. The light is assumed to be nearly collimated. 
	NOTE: The output from second iris should be uniform when checked by naked eyes.</li>
	<li>Steer the collimated beam to a Lloyd's mirror interferometer. The Lloyd's setup contains a prism-based sample holder and a 5.04 cm mirror positioned perpendicular to it. The direct and reflected illuminations together create a stable standing wave along the sample surface for patterning. The prism acts as an antireflection device. 
	NOTE: The period P of the standing wave can be written as: <img alt="Diffraction formula \( P = \lambda/(2\sin\alpha) \), mathematical equation." src="/files/ftp_upload/56735/56735eq9.jpg" data-altupdatedat="1788250015000" data-alt="Equation 9">, where λ = 325 nm and α is the incident angle with respect to sample normal, as is shown in Figure 1. The incident angle can be tuned by rotating the Lloyd's setup.</li>
</ol>
2. Periodic Array Preparation
NOTE: The sample is prepared under the standard procedure suggested by the manufacturer. All the procedures are performed at room temperature.
<ol>
	<li>Use a 1 cm2 glass substrate. Clean the glass with methanol and acetone for 10 min each in an ultrasonic bath and then pre-bake it on a hot plate at 200 °C for 1 h to remove dirt.</li>
	<li>Spin-coat the glass substrate with a 5 nm thick adhesion layer and a 100 nm thick negative SU-8 photoresist with a two-speed spin-coater.
	<ol>
		<li>Dilute the SU-8 photoresist with Gamma-Butyrolactone in a ratio of 1:5 (v/v) so that the thickness can be controlled close to 100 nm after spin-coating.</li>
		<li>Dispense 3-5 drops (0.2 mL) of adhesion solution on the glass substrate and spin at 600 rpm for 10 s and 3600 rpm for 1 min, consecutively.</li>
		<li>Repeat step 2.2.2 with 5-7 (0.3 mL) drops of diluted SU-8 from step 2.2.1 at the same speed. 
		NOTE: The adhesion layer improves the adhesion between the glass substrate and the photoresist so that the photoresist would not peel off during developing. The thickness of the SU-8 layer is controlled by the concentration and the speed of spin-coater.</li>
	</ol>
	</li>
	<li>Prebake the sample on 65 °C and 95 °C hotplates for 1 min each. Ovens are not recommended here.</li>
	<li>Transfer the sample to the prism in the interferometer. Add a drop of refractive index matching oil (n=1.45) to attach the sample on the prism. Place it as close to the mirror as possible. 
	NOTE: The sample is attached on prism surface due to the surface tension of the oil. The refractive index of oil is chosen to be the same as prism and glass substrate to eliminate back reflection from the interference.</li>
	<li>For a two-dimensional square lattice, expose the sample twice with the same exposure time but orthogonal directions; that is, expose the sample and then rotate it by 90° for the second exposure. When the photoresist is exposed to a 325 nm light, it crosslinks and cannot be dissolved by the SU-8 developer. 
	NOTE: The diameter D of the array can be controlled by adjusting the exposure time.</li>
	<li>Hard bake the sample at 65 °C and 95 °C for 2 min to prevent film cracking.</li>
	<li>Immerse the whole sample in developer for 2 min with continuous agitation to dissolve the unexposed area.</li>
	<li>Immerse the sample in isopropyl alcohol for 1 min to rinse the residuals and then dry it with compressed air. A nanohole array is then produced.</li>
</ol>
3. Gold Film Deposition and Light Emitter Coating
<ol>
	<li>Attach the sample to the sample holder of the radio-frequency magnetron sputtering deposition system with double-sided tape for Au film deposition.</li>
	<li>Pump down the chamber to a 2x10-6 Torr base pressure using a turbomolecular pump and then back fill it with 6x10-3 Torr ultra-high purity Ar gas.</li>
	<li>Use a 5 cm diameter 99.9% Au target and place a shutter between the sample and the target. Use low power (50 W) to reduce the deposition rate as well as the surface roughness. With the shutter closed, pre-sputter the target for 10 min to remove dirt.</li>
	<li>Open the shutter to process deposition at room temperature for 20 min. A film thickness of 100 nm is routinely deposited to ensure that the plasmonic system is optically thick with no transmission.</li>
	<li>Once the sample is ready, spin-coat the light emitting materials such as organic dyes or quantum dots on the metal surface to form a thin layer of dielectrics.
	<ol>
		<li>For the styryl 8 dye used in the reference9, dissolve 20 µg of styryl 8 and 500 µg of polyvinyl alcohol polymer (PVA) in 5 mL of methanol.</li>
		<li>Dispense 3-5 drops (0.2 mL) of dye solution on the sample and spin at 600 rpm for 10 s and 3600 rpm for 1 min consecutively. The thickness is estimated to be 80 nm. 
		NOTE: Water soluble or insoluble polymer can be used as anchoring material depending on the type of emitting material. However, the polymer should be non-emissive so that it would not interfere with the photoluminescence measurements. Polyvinyl alcohol polymer (PVA) is recommended for dissolving water-soluble dyes such as rhodamine 6G and styryl 8.</li>
	</ol>
	</li>
</ol>
4. Reflectivity Measurements for Determining the SPP Decay Rates
NOTE: The polarization- and angle-resolved reflectivity spectroscopy setup is shown in Figure 2. It consists of a goniometer with three rotation stages for independently changing the sample orientation (stage 1) and detection angle (stage 2) as well as the sample azimuthal angle (stage 3).
<ol>
	<li>Use a broadband white light from a quartz lamp as the light source. First couple it to a multimode fiber bundle and then collimate it by a pair of collinear face-to-face objective lenses (5X and 60X). Illuminate the light beam on the sample at different incident angles by changing sample orientation. Place a pair of incident polarizer and detection analyzer before and after the sample for polarization-dependent measurements. 
	NOTE: The face to face objectives act as a lens system that collimates and expands the white light source from the multimode fiber.</li>
	<li>Use a multimode fiber to collect the specular reflection from the sample, which is connected to a spectrometer and a CCD detector for spectroscopy.</li>
	<li>Align the setup carefully to ensure both the sample orientation stage and detection rotation stages are concentric, i.e., their rotation axes are collinear.</li>
	<li>Calibrate the setup with a flat Au film. Measure the reflection spectra at different incident angles and compare them with the theoretical reflection spectra calculated by Fresnel equations using a known Au dielectric function. The two sets of data should be consistent with less than 5% of error.</li>
	<li>Once the setup is ready, measure the linearly polarized, p or s, reflection spectra of the sample at different incident angles. The step size of the incident angle is 0.5° and the wavelength resolution is 0.66 nm. To collect the spectra under multiple incident angles, a control program is written for automation including the mechanical motion, shutter control, data acquisition, background subtraction, etc. 
	NOTE: This step is done computationally. The program is available upon request. Please send an email to the corresponding author for the source code if needed.</li>
	<li>Contour plot the reflectivity vs. wavelength and incident angle to obtain the dispersion relation of the plasmonic system for mode identification and decay rate determination. 
	NOTE: The sample azimuthal angle is to locate the position in the Brillouin zone. For example, for square lattice sample, rotate the sample azimuthally so that one of its periods is parallel with the incident plane and this defines the Γ-X direction. Rotate the sample by 45° to define the Γ-M direction.</li>
	<li>If the incident polarized is set at 45° with respect to the incident plane and the analyzer is at -45°, measure the orthogonal, or cross-polarized, reflectivity mapping.</li>
	<li>Extract the p-polarized and orthogonal reflection spectra and fit them by using CMT9,12,13, as described in the Discussion to determine the decay rates of SPPs.</li>
</ol>
5. Photoluminescence Measurements for Determining the Emission Power Ratio
Note: The angle- and polarization-resolved photoluminescence setup is shown in Figure 3.
<ol>
	<li>Replace the broadband light source with 514 nm argon ion or 633 nm HeNe laser. Use a laser line filter with a full width half maximum (FWHM) less than 5 nm to clean the laser spectrally and place a half-wave plate to control the polarization state of the laser beam. The goniometer and the detection unit remain unchanged. Place a notch filter before the detection unit to remove the laser line, which buries the luminescence. 
	NOTE: The wavelength of the laser depends on the type of emitting materials. Higher photon energy is required to excite the material with shorter emission wavelength.</li>
	<li>To measure the emission power ratio for Eq. (2) &amp; (3), conduct two types of measurements: the detection and incident scans. The interplay between the incident and detection scans assist in determining <img alt="Static equilibrium equation, ΣFx=0, vector diagram illustrating forces balance, educational use." src="/files/ftp_upload/56735/56735eq10.jpg" data-altupdatedat="1788250015000" data-alt="Equation 10">, <img alt="Pd^w/o equation symbol, relevant for fluid dynamics or thermodynamics studies." src="/files/ftp_upload/56735/56735eq11.jpg" data-altupdatedat="1788250015000" data-alt="Equation 11">, <img alt="Static equilibrium symbol, diagram; ΣFx=0, MA=0; for educational, research use." src="/files/ftp_upload/56735/56735eq12.jpg" data-altupdatedat="1788250015000" data-alt="Equation 12">, and <img alt="Static equilibrium diagram, ΣFx=0, equation shows balance of forces, educational physics tool." src="/files/ftp_upload/56735/56735eq13.jpg" data-altupdatedat="1788250015000" data-alt="Equation 13">.</li>
	<li>For the incident scan, vary the incident angle continuously but fix the detection angle with respect to the sample normal. 
	NOTE: This step is done computationally. This configuration selectively excites the incoming SPPs, which are incident angle dependent, while monitoring the variation of the emission under the chosen detection angle. In other words, the emission increases when the incident angle fulfills the phase matching equation in Eq. (1).
	<ol>
		<li>Contour plot the photoluminescence spectra against wavelength and the incident angle for the incident scan mapping. Measure the mappings for different detection angles but the relative intensities are found the same. Therefore, the incident scan probes the effect of the incoming SPPs on the emission or simply the excitation enhancement, which allows us to measure <img alt="Static equilibrium equation, ΣFx=0, vector diagram illustrating forces balance, educational use." src="/files/ftp_upload/56735/56735eq10.jpg" data-altupdatedat="1788250015000" data-alt="Equation 10"> and <img alt="Pd^w/o equation symbol, relevant for fluid dynamics or thermodynamics studies." src="/files/ftp_upload/56735/56735eq11.jpg" data-altupdatedat="1788250015000" data-alt="Equation 11">.</li>
	</ol>
	</li>
	<li>For the detection scan, fix the incident angle with respect to the sample normal but vary the detection angle. 
	NOTE: This step is done computationally.
	<ol>
		<li>Similarly, contour plot the photoluminescence spectra with wavelength and detection angle yields the detection scan mapping. As the SPP emission arises from the radiation damping of SPPs, the emission is strongly detection angle dependent. Therefore, under constant excitation, the emission increases when the detection angle fulfills Eq. (1). This configuration probes the emission enhancement and allows us to determine <img alt="Static equilibrium symbol, diagram; ΣFx=0, MA=0; for educational, research use." src="/files/ftp_upload/56735/56735eq12.jpg" data-altupdatedat="1788250015000" data-alt="Equation 12"> for different αth order as long as it has well-defined detection angle dependence.</li>
	</ol>
	</li>
</ol>

<ol><li>Okamoto, K., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Surface-plasmon-enhanced+light+emitters+based+on+InGaN+quantum+wells%5BTitle%5D)+AND+%22Nature+Materials%22%5BJournal%5D)">Surface-plasmon-enhanced light emitters based on InGaN quantum wells.</a> Nature Materials. 3 (9), 601-605 (2004).</li>
<li>Akselrod, G. M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Leveraging+Nanocavity+Harmonics+for+Control+of+Optical+Processes+in+2D+Semiconductors%5BTitle%5D)+AND+%22Nano+Letters%22%5BJournal%5D)">Leveraging Nanocavity Harmonics for Control of Optical Processes in 2D Semiconductors.</a> Nano Letters. 15 (5), 3578-3584 (2015).</li>
<li>Gontijo, I., et al. <a target="_blank" href="https://journals.aps.org/prb/abstract/10.1103/PhysRevB.60.11564">Coupling of InGaN quantum-well photoluminescence to silver surface plasmons.</a> Physical Review B. 60 (16), 11564(1999).</li>
<li>Huang, K. C. Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Antenna+electrodes+for+controlling+electroluminescence%5BTitle%5D)+AND+%22Nature+Communications%22%5BJournal%5D)">Antenna electrodes for controlling electroluminescence.</a> Nature Communications. 3, 1005(2012).</li>
<li>Atwater, H. A., Polman, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Plasmonics+for+improved+photovoltaic+devices%5BTitle%5D)+AND+%22Nature+Materials%22%5BJournal%5D)">Plasmonics for improved photovoltaic devices.</a> Nature Materials. 9 (3), 205-213 (2010).</li>
<li>Anker, J. N., et al. <a target="_blank" href="https://www.nature.com/articles/nmat2162">Biosensing with plasmonic nanosensors.</a> Nature Materials. 7 (6), 442-453 (2008).</li>
<li>Chen, Y., et al. <a target="_blank" href="http://aip.scitation.org/doi/full/10.1063/1.2956391">Excitation enhancement of CdSe quantum dots by single metal nanoparticles.</a> Applied Physics Letters. 93 (5), 053106(2008).</li>
<li>Birowosuto, M. D., Skipetrov, S. E., Vos, W. L., Mosk, A. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Observation+of+Spatial+Fluctuations+of+the+Local+Density+of+States+in+Random+Photonic+Media%5BTitle%5D)+AND+%22Physical+Review+Letters%22%5BJournal%5D)">Observation of Spatial Fluctuations of the Local Density of States in Random Photonic Media.</a> Physical Review Letters. 105 (1), 013904(2010).</li>
<li>Cao, Z. L., Ong, H. C. <a target="_blank" href="http://aip.scitation.org/doi/full/10.1063/1.4811749">Determination of coupling rate of light emitter to surface plasmon polaritons supported on nanohole array.</a> Applied Physics Letters. 102 (24), 241109(2013).</li>
<li>Lin, M., Cao, Z. L., Ong, H. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Determination+of+the+excitation+rate+of+quantum+dots+mediated+by+momentum-resolved+Bloch-like+surface+plasmon+polaritons%5BTitle%5D)+AND+%22Optics+Express%22%5BJournal%5D)">Determination of the excitation rate of quantum dots mediated by momentum-resolved Bloch-like surface plasmon polaritons.</a> Optics Express. 25 (6), 6029-6103 (2017).</li>
<li>Nikolaev, I. S., Lodahl, P., Driel, A. F. V., Koenderink, A. F., Vos, W. L. <a target="_blank" href="https://journals.aps.org/prb/abstract/10.1103/PhysRevB.75.115302">Strongly nonexponential time-resolved fluorescence of quantum-dot ensembles in three-dimensional photonic crystals.</a> Physical Review B. 75 (11), 115302(2007).</li>
<li>Cao, Z. L., Lo, H. Y., Ong, H. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Determination+of+absorption+and+radiative+decay+rates+of+surface+plasmon+polaritons+from+nanohole+array%5BTitle%5D)+AND+%22Optics+Letters%22%5BJournal%5D)">Determination of absorption and radiative decay rates of surface plasmon polaritons from nanohole array.</a> Optics Letters. 37 (24), 5166-5168 (2012).</li>
<li>Haus, H. A. <a target="_blank" href="http://scholar.google.com/scholar?hl=en&safe=off&q=author%3aHaus%2C+HA+%22Waves+and+Fields+in+Optoelectronics%22">Waves and Fields in Optoelectronics</a>. , Prentice-Hall. Englewood Cliffs, N.J. (1984).</li>
</ol>

The authors declare that they have no competing financial interests.

In this protocol, there are several critical steps. First, mechanical stability is crucial in sample preparation. The standing wave generated by Lloyd's setup is sensitive to the phase difference between two illumination beams. Therefore, any vibration during the exposure time will degrade the uniformity and edge sharpness of the nanohole. It is highly recommended to operate in a vibration-free environment, e.g., an optical table with vibration isolation supports. In addition, high power laser is also desired to...

Surface plasmon mediated fluorescence (SPMF) has received considerable attention recently1,2,3,4,5,6. When light emitters are placed in close proximity to a plasmonic system, energy can be transferred between the emitters and surface plasmon polaritons (SPPs). In general, the strong plasmonic fields can strongly enhance the excitation of the emitters2. At the same time, the emission rate is also increased because of the large density-of-states created by SPPs, yielding the well-known Purcell effect3. These two processes work hand in hand in producing the SPMF. As SPMF has stimulated numerous applications in solid-state lighting1,4, energy harvesting5, and bio-detection6, it is currently under intensive investigation. In particular, the knowledge of the energy transfer rates from the SPPs to the emitters and vice versa, i.e., the excitation and coupling rates, is of great importance. However, the excitation and emission processes are usually entangled together, study on this aspect is still lacking. For example, most of the studies only determine the excitation efficiency ratio, which simply compares the emission with and without SPPs7. The exact measurement of the excitation rate is still missing. On the other hand, conventional time-resolved techniques such as fluorescence lifetime spectroscopy are routinely used for studying the dynamics of the emission process, but they are unable to separate the coupling rate from the total decay rate8. Here, we describe how one can determine them by combining the rate equation model and the temporal coupled mode theory9,10. Remarkably, we find that the excitation and coupling rates can be expressed in terms of measurable quantities, which can be accessed by performing angle- and polarization-resolved reflectivity and photoluminescence spectroscopy. We will first outline the formulation and then describe the instrumentation in detail. This approach is entirely frequency domain based and it does not require any time-resolved accessories such as ultra-fast lasers and time-correlated single-photon counters, which are expensive and sometimes difficult to implement8,11. We anticipate this technique to be an enabling technology for determining the excitation and coupling rates between light emitters and resonant cavities.
The SPMF in periodic systems is briefed here. For a periodic plasmonic system where Bloch-like SPPs can be generated, other than direct excitation and emission, which are characterized by the excitation efficiency η and spontaneous emission rate Γr, the emitters can be excited by incoming SPPs and decay via outgoing SPPs. In other words, under resonance excitation, incoming SPPs are generated to create strong plasmonic fields that energize the emitters. Once the emitters are excited, energy from them can be transferred to outgoing SPPs, which subsequently radiatively dissipate to far-field, giving rise to enhanced emission. They define SPMF. For simple two-level emitters, the excitation refers to the increased transition of electrons from the ground to the excited states whereas the emission defines the decay of electrons back to the ground states, accompanied by photon emission at wavelengths defined by the energy difference between the excited and ground states. The excitation and emission conditions for the SPMF are required to fulfill the well-known phase matching equation to excite the incoming and outgoing SPPs9
<img alt="Grating equation in optical diffraction analysis; formula for diffraction efficiency study; equation." src="/files/ftp_upload/56735/56735eq1.jpg" data-altupdatedat="1788250015000" data-alt="Equation 1"> (1)
where εa and εm are the dielectric constants of the dielectrics and the metal, θ and φ are the incident and azimuthal angles, P is the period of the array, λ is the excitation or emission wavelength, and m and n are the integers specifying the order of SPPs. For excitation, the in-plane wavevector of the laser beam will be Bragg scattered to momentum match with the incoming SPPs and the θ and φ together define the specified incident configuration for exciting the SPPs to enhance the electronic absorption at the excitation wavelength λex. Likewise, for the emission, the outgoing SPPs will be reversely Bragg scattered to match with the light line and the angles now represent the possible emission channels at the emission wavelength λem. However, it is noted that as the emitters can couple their energy to vectorial propagating SPPs with <img alt="Surface plasmon polariton wavevector formula, \(\vec{k}_{spp}\), key in photonic optical studies." src="/files/ftp_upload/56735/56735eq2.jpg" data-altupdatedat="1788250015000" data-alt="Equation 2"> that has the same magnitude <img alt="Surface plasmon propagation; equation: |k_spp|= (2π/λ_em)√(ε_aε_m/(ε_m+ε_a)); optical studies" src="/files/ftp_upload/56735/56735eq3.jpg" data-altupdatedat="1788250015000" data-alt="Equation 3"> but different directions, the SPPs can decay via various combination of (m,n) to far-field following Eq. (1).
By using the rate equation model and temporal coupled mode theory (CMT), we find that the excitation rate Γex, i.e., the energy transfer rate from SPPs to emitters, can be expressed as9,12,13
<img alt="Optical excitation formula, Γex, diagram, relevant for photonic studies, absorption analysis." src="/files/ftp_upload/56735/56735eq4.jpg" data-altupdatedat="1788250015000" data-alt="Equation 4"> (2)
where η is the aforementioned direct excitation rate in the absence of the incoming SPPs, Γtot is the total decay rate of the incoming SPPs <img alt="Equilibrium equation Γabs, Γrad, Γex in photonics study, absorption, emission rates diagram." src="/files/ftp_upload/56735/56735eq5.jpg" data-altupdatedat="1788250015000" data-alt="Equation 5"> in which Γabs and Γrad are the Ohmic absorption and radiative decay rates of SPPs, and <img alt="Equation of power ratios in fluid dynamics, featuring Pw/Po as a mathematical expression." src="/files/ftp_upload/56735/56735eq6.jpg" data-altupdatedat="1788250015000" data-alt="Equation 6"> is the photoluminescence power ratio with and without the incoming SPPs. On the other hand, the coupling rate Γc, i.e., the energy transfer rate from emitters to SPPs, can be written as:
<img alt="Plasmonic coupling equation; diagram for photonic study; formula for optical excitation analysis." src="/files/ftp_upload/56735/56735eq7.jpg" data-altupdatedat="1788250015000" data-alt="Equation 7"> (3)
where Γr is the direct emission rate, <img alt="Equation of static equilibrium, showing Pspp,k,a/Pd ratio for scientific analysis." src="/files/ftp_upload/56735/56735eq8.jpg" data-altupdatedat="1788250015000" data-alt="Equation 8"> is the photoluminescence power ratio between the αth SPP mediated decay and direct ports, and Γradα and Γtot are the radiative decay rates for the αth port and the total decay rates. We will see that while all the SPP decay rates can be measured by reflectivity spectroscopy, the emission power ratio can be determined by photoluminescence spectroscopy. Details of the formulations can be found in reference9,10.

<table><tbody><tr><td>SU-8</td><td>MicroChem</td><td>SU-8 2000.5</td><td></td></tr><tr><td>Adhesion solution</td><td>MicroChem</td><td>Omnicoat</td><td></td></tr><tr><td>SU-8 Thinner (Gamma-Butyrolactone)</td><td>MicroChem</td><td>SU-8 2000 Thinner</td><td></td></tr><tr><td>SU-8 Developer</td><td>MicroChem</td><td>SU-8 Developer</td><td></td></tr><tr><td>Spin Coater</td><td>Chemat Technology</td><td>KW-4A</td><td></td></tr><tr><td>HeCd laser</td><td>KIMMON KOHA CO., LTd</td><td>IK3552R-G</td><td></td></tr><tr><td>Shutter</td><td>Thorlabs</td><td>SH05</td><td></td></tr><tr><td>Objective for sample preparation</td><td>Newport</td><td>U-13X</td><td></td></tr><tr><td>Pinhole</td><td>Newport</td><td>PNH-50</td><td></td></tr><tr><td>Iris</td><td>Newport</td><td>M-DI47.50</td><td></td></tr><tr><td>Prism</td><td>Thorlabs</td><td>PS611</td><td></td></tr><tr><td>Rotation stage for sample preparation</td><td>Newport</td><td>481-A</td><td></td></tr><tr><td>Supttering Deposition System</td><td>Homemade</td><td></td><td></td></tr><tr><td>Rotation Stage 1</td><td>Newport</td><td>URM80ACC</td><td></td></tr><tr><td>Rotation Stage 2</td><td>Newport</td><td>RV120PP</td><td></td></tr><tr><td>Rotation Stage 3</td><td>Newport</td><td>SR50PP</td><td></td></tr><tr><td>Detection arm</td><td>Homemade</td><td></td><td></td></tr><tr><td>Quartz lamp</td><td>Newport</td><td>66884</td><td></td></tr><tr><td>Fiber Bundle</td><td>Newport</td><td>77578</td><td></td></tr><tr><td>Objective for measurement</td><td>Newport</td><td>M-5X &amp;amp; M-60X</td><td></td></tr><tr><td>Polarizer &amp;amp; Analyzer</td><td>Thorlabs</td><td>GT15</td><td></td></tr><tr><td>Multimode Fiber</td><td>Thorlabs</td><td>BFL105LS02</td><td></td></tr><tr><td>Spectrometer</td><td>Newport</td><td>MS260i</td><td></td></tr><tr><td>CCD</td><td>Andor</td><td>DV420-OE</td><td></td></tr><tr><td>514nm Argon Ion Laser</td><td>Spectra-Physics</td><td>177-G01</td><td></td></tr><tr><td>633nm HeNe Laser</td><td>Newport</td><td>R-32413</td><td></td></tr><tr><td>CdSeTe quantum dot</td><td>Thermo Fisher Scientific</td><td>q21061mp</td><td></td></tr><tr><td>Polyvinyl alcohol polymer (PVA)</td><td>SIGMA-ALDRICH</td><td>363073</td><td></td></tr><tr><td>Control program</td><td>National Instruments</td><td>LabVIEW</td><td></td></tr></tbody></table>

determination of the excitation and coupling rates between light emitters and surface plasmon polaritons

Determination of the Excitation and Coupling Rates Between Light Emitters and Surface Plasmon Polaritons

We have developed a unique method to measure the excitation and coupling rates between the light emitters and surface plasmon polaritons (SPPs) arising from metallic periodic arrays without involving time-resolved techniques. We have formulated the rates by quantities that can be measured by simple optical measurements. The instrumentation based on angle- and polarization-resolved reflectivity and photoluminescence spectroscopy will be described in detail here. Our approach is intriguing due to its simplicity, which requires routine optics and several mechanical stages, and thus is highly affordable to most of the research laboratories.

An example of an Au periodic array is given in the inset of Figure 4a8. The plane view SEM image shows that the sample is a 2D square lattice circular hole array with a period of 510 nm, a hole depth of 280 nm, and a hole diameter of 140 nm. The p-polarized reflectivity mapping taken along the Γ-X direction is shown in Figure 4a. The dash line is calculated by the phase matching equation Eq. (1) indicating...

This protocol describes the instrumentation for determining the excitation and coupling rates between light emitters and Bloch-like surface plasmon polaritons arising from periodic arrays.

We have developed a unique method to measure the excitation and coupling rates between the light emitters and surface plasmon polaritons (SPPs) arising ...

determination-excitation-coupling-rates-between-light-emitters

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Plasmonic tweezers and photonic crystal nanostructures are shown to produce useful enhancements in the efficiency and orientation control of optically trapping micro- and nano-particles.

Utilization of Plasmonic and Photonic Crystal Nanostructures for Enhanced Micro- and Nanoparticle Manipulation

This video demonstrates localized surface plasmon resonance imaging to detect protein secretions from a single cell. Using a microfluidic setup and a peptide-bound plasmonic nanostructure chip, changes in reflected light intensity at the resonance angle reveal interactions with secreted proteins from a single cell.

Localized Surface Plasmon Resonance Imaging to Detect Protein Secretions from a Single Cell

We describe methods for the design, fabrication, and experimental characterization of plasmonic photoconductive emitters, which offer two orders of magnitude higher terahertz power levels compared to conventional photoconductive emitters.

Design, Fabrication, and Experimental Characterization of Plasmonic Photoconductive Terahertz Emitters

Silver nanowires can simultaneously transport electrons and optical information in the form of surface plasmons. A procedure is described here to realize such a shared circuitry and the limitations at propagating both information carriers are evaluated.

Evaluating Plasmonic Transport in Current-carrying Silver Nanowires

Saturable and reverse saturable scattering were discovered in isolated plasmonic particles and adopted as a novel non-bleaching contrast method in super-resolution microscopy. Here the experimental procedures of detecting and extracting nonlinear scattering are explained in detail, as well as how to enhance resolution with the aid of saturated excitation microscopy.

Measurement of Scattering Nonlinearities from a Single Plasmonic Nanoparticle

The synthesis of uniform gold nanoparticles coated with semiconductor shells of CdS or ZnS is performed. The semiconductor coating is conducted by first depositing a silver sulfide shell and exchanging the silver cations for zinc or cadmium cations.

Synthesis, Characterization, and Functionalization of Hybrid Au/CdS and Au/ZnS Core/Shell Nanoparticles

The goal of this protocol is to detail a proven approach for the preparation of plasmonic nanoparticle samples and for performing single particle spectroscopy on them with differential interference contrast (DIC) microscopy.

Performing Spectroscopy on Plasmonic Nanoparticles with Transmission-Based Nomarski-Type Differential Interference Contrast Microscopy

Photonic band structure enables understanding how confined electromagnetic modes propagate within a photonic crystal. In photonic crystals that incorporate magnetic elements, such confined and resonant optical modes are accompanied by enhanced and modified magneto-optical activity. We describe a measurement procedure to extract the magneto-optical band structure by Fourier space microscopy.

Spectral and Angle-Resolved Magneto-Optical Characterization of Photonic Nanostructures

The present protocol describes a convenient approach to integrating optical trapping and surface-enhanced Raman spectroscopy (SERS) to manipulate plasmonic nanoparticles for sensitive molecular detection. Without aggregating agents, the trapping laser assembles plasmonic nanoparticles to enhance the SERS signals of target analytes for in situ spectroscopic measurements.

Optical Trapping of Plasmonic Nanoparticles for In Situ Surface-Enhanced Raman Spectroscopy Characterizations

This paper describes how polarization-sensitive two-photon microscopy could be applied to characterize the local organization within label-free amyloid superstructures-spherulites. It also describes how to prepare and measure the sample, assemble the required setup, and analyze the data to obtain information about the local organization of amyloid fibrils.

Polarization-Sensitive Two-Photon Microscopy for a Label-Free Amyloid Structural Characterization

Learn to measure excitation and coupling rates between light emitters and surface plasmon polaritons using angle-resolved reflectivity and photoluminescence spectroscopy. This accessible method enables fluorescence enhancement studies without complex time-resolved instrumentation.

Determination of the Excitation and Coupling Rates Between Light Emitters and Surface Plasmon Polaritons

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