Miniature, sub-nanometer resolution Talbot spectrometer

Ye, Erika; Atabaki, Amir H.; Han, Ningren; Ram, Rajeev J.

doi:10.1364/ol.41.002434

Cited by 26 publications

(4 citation statements)

References 16 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…These observations are consistent with those of earlier works reported in the literature 18–20 . A few papers providing an in-depth analysis behind such behavior have also been published 18,20,43,44 .…”

Section: Resultsmentioning

confidence: 99%

A Computational Design Framework for Efficient, Fabrication Error-Tolerant, Planar THz Diffractive Optical Elements

Banerji

Sensale‐Rodriguez

2019

Sci Rep

View full text Add to dashboard Cite

We demonstrate ultra-thin (1.5-3λ 0 ), fabrication-error tolerant efficient diffractive terahertz (THz) optical elements designed using a computer-aided optimization-based search algorithm. The basic operation of these components is modeled using scalar diffraction of electromagnetic waves through a pixelated multi-level 3D-printed polymer structure. Through the proposed design framework, we demonstrate the design of various ultrathin planar THz optical elements, namely ( i ) a high Numerical Aperture (N.A.), broadband aberration rectified spherical lens (0.1 THz–0.3 THz), ( ii ) a spectral splitter (0.3 THz–0.6 THz) and ( iii ) an on-axis broadband transmissive hologram (0.3 THz–0.5 THz). Such an all-dielectric computational design-based approach is advantageous against metallic or dielectric metasurfaces from the perspective that it incorporates all the inherent structural advantages associated with a scalar diffraction based approach, such as ( i ) ease of modeling, ( ii ) substrate-less facile manufacturing, ( iii ) planar geometry, ( iv ) high efficiency along with (v) broadband operation, ( vi ) area scalability and ( vii ) fabrication error-tolerance. With scalability and error tolerance being two major bottlenecks of previous design strategies. This work is therefore, a significant step towards the design of THz optical elements by bridging the gap between structural and computational design i.e. through a hybrid design-based approach enabling considerably less computational resources than the previous state of the art. Furthermore, the approach used herein can be expanded to a myriad of optical elements at any wavelength regime.

show abstract

Section: Resultsmentioning

confidence: 99%

A Computational Design Framework for Efficient, Fabrication Error-Tolerant, Planar THz Diffractive Optical Elements

Banerji

Sensale‐Rodriguez

2019

Sci Rep

View full text Add to dashboard Cite

show abstract

“…Devices such as those marketed by Ocean Insight have supported the creation of a handheld optical spectroscopic instrument out of any light source that carries data and have already been employed for plasma spectrometers [ 70 ]. They have sub-nanometer resolution [ 71 ] and today you can purchase a spectrometer for your phone [ 72 ]. There are cell phone spectrometers that use sunlight for the source with a cuvette to measure absorbance [ 73 ].…”

Section: Detectorsmentioning

confidence: 99%

Moving toward a Handheld “Plasma” Spectrometer for Elemental Analysis, Putting the Power of the Atom (Ion) in the Palm of Your Hand

Buckley

Doherty

2021

Molecules

View full text Add to dashboard Cite

Many of the current innovations in instrument design have been focused on making them smaller, more rugged, and eventually field transportable. The ultimate application is obvious, carrying the instrument to the field for real time sample analysis without the need for a support laboratory. Real time data are priceless when screening either biological or environmental samples, as mitigation strategies can be initiated immediately upon the discovery that contaminant metals are present in a location they were not intended to be. Additionally, smaller “handheld” instruments generally require less sample for analysis, possibly increasing sensitivity, another advantage to instrument miniaturization. While many other instruments can be made smaller just by using available micro-technologies (e.g., eNose), shrinking an ICP-MS or AES to something someone might carry in a backpack or pocket is now closer to reality than in the past, and can be traced to its origins based on a component-by-component evaluation. While the optical and mass spectrometers continue to shrink in size, the ion/excitation source remains a challenge as a tradeoff exists between excitation capabilities and the power requirements for the plasma’s generation. Other supporting elements have only recently become small enough for transport. A systematic review of both where the plasma spectrometer started and the evolution of technologies currently available may provide the roadmap necessary to miniaturize the spectrometer. We identify criteria on a component-by-component basis that need to be addressed in designing a miniaturized device and recognize components (e.g., source) that probably require further optimization. For example, the excitation/ionization source must be energetic enough to take a metal from a solid state to its ionic state. Previously, a plasma required a radio frequency generator or high-power DC source, but excitation can now be accomplished with non-thermal (cold) plasma sources. Sample introduction, for solids, liquids, and gasses, presents challenges for all sources in a field instrument. Next, the interface between source and a mass detector usually requires pressure reduction techniques to get an ion from plasma to the spectrometer. Currently, plasma mass spectrometers are field ready but not necessarily handheld. Optical emission spectrometers are already capable of getting photons to the detector but could eventually be connected to your phone. Inert plasma gas generation is close to field ready if nitrogen generators can be miniaturized. Many of these components are already commercially available or at least have been reported in the literature. Comparisons to other “handheld” elemental analysis devices that employ XRF, LIBS, and electrochemical methods (and their limitations) demonstrate that a “cold” plasma-based spectrometer can be more than competitive. Migrating the cold plasma from an emission only source to a mass spectrometer source, would allow both analyte identification and potentially source apportionment through isotopic fingerprinting, and may be the last major hurdle to overcome. Finally, we offer a possible design to aid in making the cold plasma source more applicable to a field deployment.

show abstract

“…Much improvement in wavelength resolution of tiltedgrating Talbot spectrometers is recently obtained with the recent advances made in digital imaging sensors. A compact lens-free spectrometer using non-paraxial mid-field diffraction provides the spectral resolution less than 1 nm [21]. With the aid of tone parameter extraction algorithms, a compact Talbot wavemeter with below 10 pm precision was reported [22].…”

Section: Introductionmentioning

confidence: 99%

Practical Talbot wavemeter

Suksawat,

Buathong,

Deachapunya

2023

Optica Applicata

View full text Add to dashboard Cite

A wavemeter using the near-field Talbot diffraction is simplified. High accuracy wavelength measurement can be obtained from each spacing between two adjacent maximum intensities of the periodicity along multiples of the Talbot distance. Our experimental results are confirmed by our calculations. In contrast to the previous works, we use a diffraction grating with sufficiently large grating period. Therefore, the setup is practical and the pixel size of camera used to measure the interference pattern can be large. Moreover, the obtained Talbot patterns are sharp without using a post-image processing. According to our recent setup, we use the grating with a period of 12.5 μm. With visible light lasers, the Talbot distances are in the range of a few hundred of micrometers. These distances are much larger than a pixel size of normal camera. An external cavity diode laser with rubidium saturated absorption spectroscopy is used to calibrate our setup. High accuracy at 1 pm can be achieved.

show abstract

Miniature, sub-nanometer resolution Talbot spectrometer

Cited by 26 publications

References 16 publications

A Computational Design Framework for Efficient, Fabrication Error-Tolerant, Planar THz Diffractive Optical Elements

A Computational Design Framework for Efficient, Fabrication Error-Tolerant, Planar THz Diffractive Optical Elements

Moving toward a Handheld “Plasma” Spectrometer for Elemental Analysis, Putting the Power of the Atom (Ion) in the Palm of Your Hand

Practical Talbot wavemeter

Contact Info

Product

Resources

About