We have built a micro-optical spectroscopy system coupled with a Nd:YLF laser heating system for performing high pressure–temperature in situ Raman measurements in diamond anvil cells (DAC). A variety of materials can be investigated, providing information about structural and dynamical properties of condensed matter under extreme conditions. We report on a method for laser heating transparent ...

Melanins are the most prevalent pigments in animals and are involved in visual communication by producing colored traits that often evolve as intraspecific signals of quality. Identifying and quantifying melanins are therefore essential to understand the function and evolution of melanin-based signals. However, the analysis of melanins is difficult due to their insolubility and the lack of simp...

Introduction: Laser Raman spectroscopy offers the exciting opportunity to interrogate rocks in their natural geological context, preserving the mineral constituents along with their textural and morphological information (Figure 1). Microscopic Raman spectroscopy is a nondestructive means of generating two dimensional maps of mineralogy on the order of grain sizes. Because of its versatility, R...

Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. The MIT Faculty has made this article openly available. Please share how this access benefits you. Your story matters. An analytical study is presented of the double resonant Raman scattering process in graphene, responsible for the D...

Ž . We have observed laser-jitter-enhanced high-resolution spectra of three hyperfine states in the ground level H of 4 Pr :Y SiO using coherent population trapping and phase-correlated four-wave mixing. We have also observed optical 2 5 Raman pulse excited two-photon spectral hole-burning. The observed high-resolution spectra are due to a laser-jitter-suppressed Raman coherence window in an in...

We demonstrate a wavelength tunable optical excitation source for coherent Raman scattering (CRS) spectroscopy based on a single femtosecond fiber laser. Electrically controlled wavelength tuning of Stokes optical pulses was achieved with soliton self frequency shift in an optical fiber, and linear frequency chirping was applied to both the pump and the Stokes waves to significantly improve the...

Time-resolved pure-rotational coherent anti-Stokes Raman spectroscopy using picosecond-duration laser pulses is investigated for gas thermometry. The use of picosecond laser pulses significantly reduces background caused by scattering of the probe beam, and delayed probing of the Raman coherence enables elimination of interference from nonresonant four-wave mixing processes. Temperatures inferr...

We have used resonance Raman scattering as a novel noninvasive optical technology to measure carotenoid antioxidants in living human tissues of healthy volunteers. By use of blue-green laser excitation, clearly distinguishable carotenoid Raman spectra superimposed on a fluorescence background are obtained. The Raman spectra are obtained within less than a minute, and the required laser light ex...

Since the original suggestions of self-trapping for laser beams 1–3 , there has been a growing interest in generation of spatial optical solitons due to their rich nonlinear dynamics, and their potential technological applications 4 . Over the last few decades, spatial optical solitons have been predicted and demonstrated in a variety of physical systems utilizing different nonlinear optical pr...

Harmonic generation using nonlinear optical crystals is currently the most efficient approach of obtaining visible and ultraviolet lasers. Diode-pumped Nd-doped solid-state lasers can operate in the blue, green, and red spectral regions by intracavity frequency doubling. However, there are few solid-state laser sources that can efficiently produce laser emission in a region covering 550 to 650 ...