Wafers Used in Single Particle Spectroscopy

university wafer substrates

What Wafers are Used in Single Particle Spectroscopy

A PhD at a international university requested a quote for the following:

"We are looking for optical grade 3-4 inch ultra thin glass and sapphire wafers for single particle spectroscopy, on which we grow Al2O3 and aluminum and do mask lithography, we need a thickness between 140-175 microns for the optical objective working distance. We are currently using Borofloat n.1 cover slides from MARIENFELD superior. If you have any of these options we would be happy to test them and get a quote for an initial order.

The application is lithography and optical microscopy on nanocrystals. The wafers need to be optical grade double side polished (use with a transmission confocal microscope with a 100x objective and 0.16mm working distance).
Regarding quantity- we will need to start with the minimal amount (5-10) for tests, later i believe we will buy 25-50 per year.
Regarding the glass type- we used borofloat up to now, but i would like to hear about options of fused silica, quartz, and sapphire if possible (the substrates later go under a TEM microscope and we have some trouble with the borofloat glass at high electron beam energy)."

For specs and pricing reference #262853 

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What is Single Particle Spectroscopy?

Single particle spectroscopy is a very useful tool in atmospheric research. There are several techniques that can be used in this method. These include Raman spectroscopy, Surface plasmon resonance, and Extinction spectra. In this article, we will look at the single particle Raman spectroscopy technique.

Time-resolved chiroptical spectroscopy

Time-resolved chiroptic single particle spectroscopy is a technique that allows scientists to observe single chiral nanoparticles in solution. The method uses an optical probe that enhances the weak chirality signals associated with chiral molecules. The probe is based on the differential interaction between left and right-circularly polarized light.

The technique has numerous applications in materials science. It has also been applied to the study of airborne aerosol particles. The first study reported by Trunk and Kiefer used solid glass spheres and nonspherical quartz particles and a Raman spectrometer. Since then, OT-RS has been used to study airborne aerosol particles. In 2004, Hopkins et al. reported the first measurements of a single MWCNT in the anodic range.

The technique is highly sensitive and precise. It can detect tiny particles, even those as small as nanometers. In addition, the particle's rotational motion is slow enough to sample all orientations in a single frame. Using a 10 nm spectral window, CDSI of a freely diffusing left-handed helix averaged over the first 60 frames of a time-series can be determined. Moreover, the CDSI changes from frame to frame, and it does so for the full spectrum.

The chiroptical response of nanoparticles is also sensitive to changes in their shape, such as rotation around the long axis. This can be attributed to the presence of chiral nanostructures. Nanoparticles exhibit a stronger optical activity than molecules, making them excellent candidates for studying nonlinear optical signals in suspensions. The engineering geometry and material composition of the nanoparticles allow for the tailoring of the chiroptical effect to suit specific applications.

Time-resolved chiroptic spectroscopy is a powerful tool for understanding biological/chemical processes. It provides quantitative insights into interactions, dynamics, and functions of molecules. In addition, it can be used to understand the properties of molecules.

Surface plasmon resonance

Surface plasmon resonance (SPR) is a phenomenon where a wave is emitted from a surface and interacts with a local irregularity. This interaction results in emitted light, which can be detected behind a thin metal film in different directions. This phenomenon is implemented in analytical instrumentation. Typical instruments consist of a light source, an input scheme, a prism with an analyte interface, a detector, and a computer.

The width of E Res shows a relationship with the electrochemical potential, with the width increasing with increasing potential. However, the resonance peak position does not change when the direction of the potential sweep is reversed. This is consistent with the charge density tuning model. In the same manner, the change points of E Res and G reflect the potential-dependent tuning of E Res.

The results of the experiment indicate that surface plasmon resonance is a useful tool to detect biopolymers. To do this, light from a single nanoparticle is directed to a spectrograph. The spectra are recorded every 2.5 s, and each spectrum is fitted with a single Lorentzian curve. Using these data, the resonance energy and full width at half maximum are determined.

A bimodal pattern in d E Res/d U behavior suggests the presence of a second process, possibly non-Faradaic charge density tuning. The latter is more prominent than the former, since it results in relatively large resonance shifts. However, the chemical process overshadows the non-Faradaic process. The effect of plasmon resonance is particularly important in single particle spectroscopy because it can allow for high-resolution images of 100 individual molecules at once.

Surface plasmon resonance imaging (SPR) has the potential to replace chromatography-based techniques. It can be used with different biopolymers and imaging sensors, and can produce images with high contrast. It is a method that is similar to Brewster angle microscopy and Langmuir-Blodgett trough.

Extinction spectra

Extinction spectra of single particles are obtained by analyzing the scattering and absorption components of a material. The extinction spectra of single particles can be determined in many ways. For instance, if a sample is composed of a gold nanoparticle with an average diameter of 60 nm, it can be determined by measuring the extinction spectrum at different wavelengths.

The LES method can be used to measure the PSDs of complex particles that have multimodal sizes and shapes. It can also be used to determine the particle concentration in colloidal suspensions, aerosols, and plasmas. In this paper, we review the basic methods of LES and explain how to use them.

An amorphous SiO 2 particle is an example of a particle that can be studied using this method. Researchers used a low-pressure argon-silane discharge to investigate the nucleation of a particle. Their results were compared with theoretical predictions of the particle's extinction spectra.

The experimental data from this study have shown that agglomerated dust grains have a strong influence on the extinction spectra. This effect is greater for small particles than for large ones. Although agglomeration is an important factor affecting extinction spectra, its precise effect on extinction spectra is still unclear.

For high-speed measurements of IR spectra, a dedicated robotic manipulator has been used. This technology allows the beam to be focused precisely to a single sample spot and maintain a high beam intensity. The beamline is also capable of a high signal-to-noise ratio. The IR spectrometer, a Thermo Fisher NIC-PLAN IR microscope, is equipped with a mercury cadmium telluride detector coupled to a NEXUS 5700 Fourier-transform infrared spectrometer. The aperture size is set to 10 x 10 m2.

Extinction spectra of single-particle spectroscopy have shown that the spectral energy corresponding to the resonance energy decreases with increasing gold content. The underlying mechanism for this effect is interband damping. The interband damping effect is attenuated at higher frequencies by the size correction term.


Single particle spectroscopy is a useful tool for studying particle processes. The spectroscopic method can be used to study particles in situ, which is a particularly useful technique when it comes to studying precipitation and evaporation processes. It is also useful for probing processes such as water vapor deposition and aging of bioaerosols.

Single particle Raman spectroscopy can be used to characterize the composition of single particles in situ, which can be advantageous for studying atmospheric processing of aerosol particles. In addition to characterizing single particles, it can also measure their size and phase state. This allows scientists to understand the chemical composition of aerosol particles and to study their interactions with other molecules.

Single particle spectroscopy is an efficient tool for observing heterogeneous reactions. It allows scientists to get a global view of particle production. It also allows for the detection of single particles, which avoids the problems associated with ensemble averaging. A single particle can be detected for an infinite time.

Single particle responses can be transformed into peaks by using mass flux calibration curves. The mass of a single particle is measured with an intensity that relates to its elemental mass. Traditionally, ICP-MS requires a calibration curve using dissolved standards. This calibration curve connects the signal intensity to the analyte concentration. The relationship between the analyte concentration and mass observed per measurement event is known as the mass flux.

Single particle Raman spectroscopy is useful for studying the uptake of amines and ammonia. Researchers have recently investigated the role of the particle's phase state in the simultaneous uptake of these substances. For example, Chan and Sauerwein studied how acidic particles in the presence of DMA and ammonia could be affected by their phase state. In this study, anhydrous acidic particles absorbed both analyte and ammonia by adsorption. They also discovered that acidic droplets displaced particulate ammonium.