Phase-matching scheme

Figure 4. Diagram (w-fi) showing phase-matching scheme for guided wave optical...

In conclusion a method of fabrication of guiding structure which is simple and suited to organic materials has been presented and optical SHG in benzil crystal cored fibres demonstrated. Also, phase matching schemes have been discussed for which the field overlap integral is maximum. 

Since the index of refraction in an atomic inert gas at a frequency far from an absorption transition is very close to 1.00, the phase matching scheme for the frequency tripling process,... 

Fig.8.41a-c. Basic diagram and phase matching schemes for Coherent Anti-Stokes Raman Scattering (CARS), (a) collinear, (b) BOXCARS, and (c) folded BOXCARS phase matching [8.91]... 

Fig.10.11. Experimental set-up for CARS spectroscopy using the BOXCARS phase matching scheme [10.15]...

Hirose et al. [26] proposed a homodyne scheme to achieve the background-free detection of the fourth-order field. With pump irradiation in a transient grating configuration, the fourth-order field propagates in a direction different from that of the second-order field because of different phase match conditions. The fourth-order field is homodyned to make ffourth(td. 2 D) and spatially filtered from the second-order response hecond td, 2 D). 

Figure 1. Phase-matching diagrams for CARS signal generation are shown in a and b. The energy diagram at the bottom shows the energy matching scheme for...

Figure 1 Schematic representation of a time-resolved coherent Raman experiment, (a) The excitation of the vibrational level is accomplished by a two-photon process the laser (L) and Stokes (S) photons are represented by vertical arrows. The wave vectors of the two pump fields determine the wave vector of the coherent excitation, kv. (b) At a later time the coherent probing process involving again two photons takes place the probe pulse and the anti-Stokes scattering are denoted by subscripts P and A, respectively. The scattering signal emitted under phase-matching conditions is a measure of the coherent excitation at the probing time, (c) Four-photon interaction scheme for the generation of coherent anti-Stokes Raman scattering of the vibrational transition.

If the crystal is close to, but not exactly at, the phase matching orientation relative to k(u> 1), then a weak 2aq beam will be generated propagating at a small angle relative to k(u 1). Minimization of this deviation angle provides a basis for servo-correction of the crystal orientation to maximize SHG. It also ensures that, as uq is scanned, the 2u>i beam pointing direction is constant, which is good news for multiple resonance schemes that require careful superposition of several beams of laser radiation. 

The cumulative energy matching scheme [41] is employed to address the energy matching between different adsorbates in the adsorbed phase. With the uniform energy distribution, it is... 

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