Single-shot stand-off chemical identification of powders using random Raman lasing

Hokr, Brett H.; Bixler, Joel N.; Noojin, Gary D.; Thomas, Robert J.; Rockwell, Benjamin A.; Yakovlev, Vladislav V.; Scully, Marlan O.

doi:10.1073/pnas.1412535111

Cited by 63 publications

(37 citation statements)

References 31 publications

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“…Nowadays, one of the research trends is the study of new physical phenomena in RLs, such as its spin glass behavior20 or Levy-like statistics in the intensity fluctuations21. Recent applications include the use of RLs as speckle-free imaging sources22 or for chemical identification of powders23.…”

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confidence: 99%

Multi-wavelength emission through self-induced second-order wave-mixing processes from a Nd3+ doped crystalline powder random laser

Moura

Jerez

Maia

et al. 2015

Sci Rep

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Random lasers (RLs) based on neodymium ions (Nd3+) doped crystalline powders rely on multiple light scattering to sustain laser oscillation. Although Stokes and anti-Stokes Nd3+ RLs have been demonstrated, the optical gain obtained up to now was possibly not large enough to produce self-frequency conversion. Here we demonstrate self-frequency upconversion from Nd3+ doped YAl3(BO3)4 monocrystals excited at 806 nm, in resonance with the Nd3+ transition 4I9/2 → 4F5/2. Besides the observation of the RL emission at 1062 nm, self-converted second-harmonic at 531 nm, and self-sum-frequency generated emission at 459 nm due to the RL and the excitation laser at 806 nm, are reported. Additionally, second-harmonic of the excitation laser at 403 nm was generated. These results exemplify the first multi-wavelength source of radiation owing to nonlinear optical effect in a Nd3+ doped crystalline powder RL. Contrary to the RLs based on dyes, this multi-wavelength light source can be used in photonic devices due to the large durability of the gain medium.

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confidence: 99%

Multi-wavelength emission through self-induced second-order wave-mixing processes from a Nd3+ doped crystalline powder random laser

Moura

Jerez

Maia

et al. 2015

Sci Rep

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“…emerging technique which may be suitable for remote chemical identification (7), as it would guarantee the signal brightness and detection efficiency (see Fig. 1).…”

Section: Significancementioning

confidence: 99%

“…6), and remote sensing (e.g., ref. 7). Comparing with other molecular-specific imaging techniques, Raman spectroscopy provides a label-free contrast mechanism, which is intrinsically induced by the molecules contained in the sample.…”

mentioning

confidence: 99%

Lightweight Raman spectroscope using time-correlated photon-counting detection

Meng

Petrov

Cheng

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

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Raman spectroscopy is an important tool in understanding chemical components of various materials. However, the excessive weight and energy consumption of a conventional CCD-based Raman spectrometer forbids its applications under extreme conditions, including unmanned aircraft vehicles (UAVs) and Mars/Moon rovers. In this article, we present a highly sensitive, shot-noise-limited, and ruggedized Raman signal acquisition using a time-correlated photon-counting system. Compared with conventional Raman spectrometers, over 95% weight, 65% energy consumption, and 70% cost could be removed through this design. This technique allows space-and UAV-based Raman spectrometers to robustly perform hyperspectral Raman acquisitions without excessive energy consumption. Comparing with other molecular-specific imaging techniques, Raman spectroscopy provides a label-free contrast mechanism, which is intrinsically induced by the molecules contained in the sample. Relying on internal properties of molecules, investigators can avoid complicated sample preparation processes and molecular-specific labeling, etc. In many imaging/sensing applications, Raman spectroscopy often provides superior molecular specificity, imaging speed, and spectral resolution, and is usually considered as an emerging imaging technique (8, 9). However, despite decades of intensive study, Raman spectroscopy is still not widely applicable in space-based detection systems including unmanned aircraft vehicles (UAVs) and Mars/Moon rovers. This is mainly due to two hurdles: the unacceptable heavy weight of conventional spectrometers, and the excessive energy consumption by the entire system, especially the CCD camera.In typical laboratory-based Raman spectroscope setups, a beam of light is focused onto the sample. The scattered photons are then collected by a condenser lens and sent into a spectrometer. A diffractive grating is usually used to induce a spatial dispersion of the Raman peaks into different wavelengths. A CCD camera is used as the detector. In this sense, a correspondence between the CCD pixel and Raman shift can be established, and the Raman peaks are recognized and recorded.However, when extending this approach to field circumstances (e.g., space-based vehicles or UAVs), several key limitations emerge. First, due to the tiny angular dispersion provided by diffractive gratings, a long optical propagation length is required to create sufficient spatial dispersion. This is usually not allowed in space-based vehicles. Moreover, this long propagation length, together with any possible moving parts contained in the grating-based spectrometers, is unable to tolerate excessive vibrations during the launching/landing process of a space-based vehicle. Furthermore, the excessive energy consumption for the CCD cameras, especially for the cooling process, is usually not affordable by UAVs or spacebased vehicles/rovers. Finally, the weight of the spectrometer is also a problem (10-12).To overcome these difficulties, investigators invented and used several differe...

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“…One of the most striking properties of the random Raman lasing emission previously reported is the presence of higher order SRS processes [17,18]. These processes are the result of the Stokes shifted field undergoing an additional SRS processes, and picking up an additional Stokes shift.…”

Section: Introductionmentioning

confidence: 99%

“…This fundamental difference in the processes leads to less heat being generated in the medium and allows much more powerful laser sources to be used without damaging the lasing medium. The more intense pump laser pulses used in random Raman lasing support tremendous gain, allowing for the generation of a very bright emission [18]. Second, the gain in random Raman lasing is fundamentally different than traditional random lasing.…”

Section: Introductionmentioning

confidence: 99%

Higher order processes in random Raman lasing

2014

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Random Raman lasers offer a unique opportunity to study many exciting dynamics of light propagation in turbid media. One of the most notable features observed to exist in the recently discovered random Raman laser are the presence of higher order stimulated Raman scattering (SRS) processes. The higher order Stokes generation likely comes from photons that have the longest pathlengths, thus have the most gain. This makes these photons particularly likely to offer interesting insight into wave propagation effects such as coherent backscattering and optical Anderson localization. In this work, we use Monte Carlo simulations to investigate how these higher order processes occur and what properties they are expected to exhibit when considering only transport equation dynamics. This knowledge will allow us to look for deviations from this theory in future experiments to determine if wavelike properties play an active role in random Raman lasing.

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Single-shot stand-off chemical identification of powders using random Raman lasing

Cited by 63 publications

References 31 publications

Multi-wavelength emission through self-induced second-order wave-mixing processes from a Nd3+ doped crystalline powder random laser

Multi-wavelength emission through self-induced second-order wave-mixing processes from a Nd3+ doped crystalline powder random laser

Lightweight Raman spectroscope using time-correlated photon-counting detection

Higher order processes in random Raman lasing

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