Use of a tunable GaAs injection laser in optoacoustic detection of absorption by hydrogen fluoride molecules

Abstract

The composition dependence of the elastic moduli E, C and C' of FCC transition metal alloys is analysed by separating it into a contribution from the change in the atomic volume and an intrinsic contribution of the electron concentration X. When the volume contribution is taken into account. there are no great differences in the X dependence of B and C in different alloy systems. Differences in the intrinsic X dependence of C' in different alloys seem to arise from magnetic effects. The values of C and C' are anomalously low in alloys with X in the neighbourhood of 8.8. B is relatively insensitive to changes in X except in the regions X < 7.7 and 8.6 < X < 8.9 where it decreases with decreasing X . The temperature dependence of all the moduli is also anomalous in these regions of X.

Towards rainbow portable Cytophone with laser diodes for global disease diagnostics

“…The general principle of the PTM system has been described in detail elsewhere 34 – 36 . Briefly, the technical platform of collinear dual-beam (pump-probe) confocal PTM imaging was based on an IX73 microscope platform (Olympus America, Inc., Central Valley, PA) with different high-pulse-rate (1–10 kHz), nanosecond (5–10 ns) lasers with fixed wavelengths (532/671/820/1064 nm) that used a combination of lens and fiber-optics to deliver laser lights to samples.…”

“…These limitations also make it extremely difficult to use an array of lasers with different wavelengths, which would aid in the spectral identification of biomarkers with different absorption spectra, also called spectral fingerprints, in particular, for NPs, Hb, and Hz 22 – 33 . Specifically, after our pioneering first application of spectrally tunable laser diodes in PA spectroscopy 34 , a few attempts were undertaken to use laser diodes for PA imaging 35 , 36 ; however, the pulse energy of laser diodes was too low (at the level of a few microjoules [µJ]) to provide sufficient sensitivity. The pulse duration was also relatively long (90–120 ns) compared to the acoustic transit time across the small target to match the acoustic confinement for high-efficiency generation of PA signals 14 , 15 .…”