Emission in the Region 4000 to 7000 Å Via Four-Photon Coupling in Glass

Development of a broadband reflectivity diagnostic for laser driven shock compression experiments

“…29. of approximately 400-1200 nm, as shown in Figure 3. 21,[31][32][33][34] As mentioned above, the spectral broadening in the dielectric material is highly nonlinear in its dependence on the laser intensity, 21,32,34,35 requiring the generation of independent spectral references for each of the time delayed pulses, as will be discussed in more detail below. The white light was collimated using a 500-mm achromat and, after passing through a notch filter to remove the excess fundamental laser light at 800 nm, injected into a 1-m-long 200-µm-diameter core high-damage threshold fiber using a 40× microscope objective.…”

“…The high photon intensities and broad spectral range required for data collection over short time-scales can be obtained using broadening of an ultra-fast laser in a dielectric medium, a method developed over the past 40 years. [19][20][21] Using this broadening technique, a considerable amount of work has been done in the last decade developing transient absorption spectroscopy of laser driven shock compressed samples. [22][23][24][25][26][27] This has provided a great deal of insight into the chemical changes accompanying compression; however, the measurements are limited to a single time point per shot and therefore does not probe time-dependent spectral changes.…”

Spectral broadening of picosecond laser pulses in optical fibres

“…If two pulses at WL and U>R are present the nondegenerate fourphoton interaction (II) w L + WR -* w 3 + w 4 is possible as well. If no signal at w 3 and u/4 is entered to the fibre, one speaks of stimulated four-photon mixing [4,5,13,[40][41][42][43], stimulated parametric four-photon interaction [44,45], stimulated four-wave parametric emission [46], or parametric four-photon generation (start from quantum noise and black-body radiation [37]). If a weak signal at either w 3 or w 4 is already present, one speaks of four-photon parametric amplification [4,5,10,47].…”

Controlled Multibeam Supercontinuum Generation With a Spatial Light Modulator

“…This phenomenon can eventually give rise to an extreme spectral broadening, ranging from the ultraviolet to the infrared regions, termed supercontinuum (SC) generation [3,4]. Currently, the ongoing research in filamentation ranges from the modeling of the process to the generation of filaments with high flexibility for many different applications.…”