Silicon Raman laser

Fig. 16.13 (a) Thermal distribution of tip and sample calculated using finite element method [111, 112]. (b) Silicon Raman peak of the tip as a function of temperature calculated from the ratio of stokes and anti-stokes Raman as shown in upper inset. Lower inset shows the simplified schematic of tip-heating-assisted TERS. (c) G-band Raman spectra at different incident laser power for varying the temperature... 

Figure 5.5. Raman spectroscopy of laser crystallized solution-processed silicon films. The plot shows laser intensity versus Raman shift of the film. The crystallinity is estimated from the intensity and width of the crystalline peak at 520 cm-1. [Reproduced with permission from Ref. 11. Copyright 2006 The Japan Society of Applied Physics.]...

D. Hill, T. Jawhari, J.G. Cespedes, J.A. Garcia and E. Bertran, In-situ monitoring of laser annealing by micro-Raman spectroscopy for hydrogenated silicon nanoparticles produced in radio frequency glow discharge, Phys. Status SolidiA, 203, 1296-1300 (2006). 

Figure 3-8 Raman microprobe spectrum of fluorinated hydrocarbon contaminant on silicon wafer that had been polished and plasma-etched (lower) and Raman spectrum of polytetrafluoro-ethylene (upper). Laser, 135 mW at 514.5 nm. Slits, 300 jon. Time, 0.5 s per data point. (Reproduced with permission from Adar, F., in Microelectronics Processing Inorganic Materials Characterization (L. A. Casper, ed.), ACS Symposium Series Vol. 295, pp. 230-239. American Chemical Society, Washington, D.C., 1986. Copyright 1986 American Chemical Society.)...

Although the peak power of the pump laser must be high, the power of the probe laser should be kept low to avoid nonlinear effects (multiphoton absorption, stimulated Raman scattering see Section 3.9.2) and dielectric breakdown (ionization of molecules) that damage the sample. Thus, signal averaging of many pulses (high repetition rate) is made to obtain acceptable S/N ratios. Multichannel detectors such as an intensified silicon photoiode... 

Xia and coworkers have demonstrated that the polarization of light plays an important role for nanoparticles with anisotropic shapes, especially with tmncated comers [77]. Optical dark-field mode imaging was employed to identify individual silver nanocubes deposited on silicon substrate as shown in Fig. 15.10a. Raman spectra were collected from the nanocubes, which were oriented in different directions with respect to the laser polarization. Subsequent SEM imaging of the same cubes enabled the authors to directly correlate the orientation of the nanocubes with respect to the light polarization and the SERS enhancement factor. They observed dramatic variation in SERS intensity when the nanocubes were oriented at different angles relative to the polarization of excitation laser as shown in Fig. 15.10b. SERS spectra of 1,4-benzenedithiol adsorbed on Ag nanocubes oriented in different directions showed different intensities with respect to the light polarization direction. The individual nanocubes with sharp comers were the most... 

The Raman spectra on solid metal substrates were measured using a Renishaw RM2000 micro-Raman apparatus, coupled with a diode laser source emitting at 785 nm. Sample irradiation was accomplished using the 50x microscope objective of a Leica microscope DMLM. The beam power was 3 mW, the laser spot diameter was adjusted between 1 and 3 pm. Raman scattering was filtered by a double holographic notch filter system and collected by an air-cooled CCD detector. The acquisition time for each measurement was 10 s. All spectra were calibrated with respect to a silicon wafer at 520 cm. ... 

Figure 8.24. Typical of Q vs. X curve for a front-illuminated silicon CCD, with Raman shift ranges (0 to 3000 cm ) for several common lasers.

Figure 5. Laser Raman spectra of steam aged crystals containing 5% V (A) HY (Linde s LZY-82), (B) Silicon-Enriched HY (Linde s LZ-210) with Si/Al = 6.1 and Na O = 0.18 wt%. ...

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