High-power terahertz optically pumped NH3 laser for plasma diagnostics

Abstract

The parameter of a terahertz (THz) laser intended for plasma diagnostics in electrodynamic accelerators and tokamaks with a strong magnetic field are discussed. Generation of THz radiation in an ammonia laser under the action of high power pulsed optical pumping by the radiation of a 10P(32) CO 2 laser is simulated numerically. The main characteristics of the output radiation, such as its spectrum, peak inten sity, time dependence, and total energy, are calculated.

NH3 laser THz emission under optical pumping by “long” (∼100 µs) CO2 laser pulses

“…Several research groups studied in detail NH 3 lasing with a wavelength of ∼152 μm for the CO 2 laser pump line 10P(32) and ∼90 μm for the 9R( 16) pump line [9][10][11][12] . Such an interest in these wavelengths of the THz NH 3 laser is apparently associated, firstly, with the high efficiency of emission conversion (1.6% for ∼152 μm [10] and 1.7% for ∼90 μm [9] ), and, secondly, with the prospect of using such THz emission for plasma diagnostics in electrodynamic accelerators and tokamaks with a strong magnetic field [13] . Therefore, for these wavelengths, in contrast to others, the shape of a THz laser pulse was studied in comparison with a pump pulse.…”

“…[4]). To arrange multifrequency THz lasing, it makes sense to study characteristics of the NH 3 laser pumped by CO 2 laser pulses with a duration that is orders of magnitude longer than the NH 3 molecule vibrational relaxation time (∼0.1 μs [13] ), i.e., an implementation of quasi-CW optical pumping.…”