Measurements of the nonlinear refractive index of air, N_2, and O_2 at 10 μm using four-wave mixing

Abstract

We report on measurements of the nonlinear index of refraction of air, N₂, and O₂ at a wavelength close to 10 μm by collinear four-wave mixing of a 200 MW CO₂ laser beat-wave. The use of a 200 ps long beat-wave comprising radiation amplified on the 10P20 and 10R16 lines of the CO₂ laser provides a sensitive method to measure the small nonlinearities characteristic of the gas phase in a spectral region where no such data exists.

Ultrashort infrared 25–11 μm pulses: spatiotemporal profiles and absolute nonlinear response of air constituents

“…The values shown for 2, are maximum at the pulsewidths indicated. (c) Pigeon et al [16,17] is the angle of from the crystal surface normal and M=45 is the pump lens demagnification factor, yields = 7.5° at = 3.0 and = 2.2° at λ = 6.5 , in very good agreement with the tilt measurements in Fig. 2(a) and (b).…”

Broadband terahertz radiation from two-color mid- and far-infrared laser filaments in air

“…The second term F NL contains the third-order nonlinear polarization P NL , the electron current J , and a loss term due to ionization [21]. Air dispersion is taken from [22] Table I with Raman-delayed response ratio x K [25,26]. The number of critical powers, P cr = λ 2 0 /2πn 2 , is kept constant and set to 1.73.…”

Optical visualization and imaging of nanomaterials

“…32 These NaCl nanocrystals exhibited unique properties such as hygroscopicity, optical transparency, solubility in water and high mobility of constituent ions under an electric field, and provided new opportunities in optics and spectroscopy. 33 During a typical procedure, a metal cover was first deposited on one side of CNTs, and then a NaCl droplet was placed on the other side. Upon application of an electric field across the CNTs using Pt wires, the CNTs could then be decorated with arrays of NaCl nanocrystals within 10 minutes through ion transportation along the exterior of the CNTs (Figure 7b).…”