Comparison of collimated blue-light generation in ⁸⁵Rb atoms via the D₁ and D₂ lines

Abstract

We experimentally studied the characteristics of the collimated blue light (CBL) produced in 85 Rb vapor by two resonant laser fields exciting atoms into the 5D 3/2 state, using either the 5P 1/2 or the 5P 3/2 intermediate state. We compared the CBL output at different values of frequency detunings, powers, and polarizations of the pump lasers in these two cases, and confirmed the observed trends using a simple theoretical model. We also demonstrated that the addition of the repump laser, preventing the accumulation of atomic population in the uncoupled hyperfine ground state, resulted in nearly an order of magnitude increase in CBL power output. Overall, we found that the 5S 1/2 − 5P 1/2 − 5D 3/2 excitation pathway results in stronger CBL generation, as we detected up to 4.25 µW using two pumps of the same linear polarization. The optimum CBL output for the 5S 1/2 − 5P 3/2 − 5D 3/2 excitation pathway required the two pump lasers to have the same circular polarization, but resulted only in a maximum CBL power of 450 nW.

Spiking dynamics of frequency upconverted field generated in continuous-wave excited rubidium vapors

“…Nonlinear parametric and nonparametric processes in atomic media generate new optical fields with substantially different wavelengths to those used for excitation [1]. The frequency conversion of continuous wave (cw) laser light with a power of several tenths of a milliwatt into directional blue, ultraviolet and mid-infrared (IR) radiation in alkali vapours continues to be an active topic of research [2][3][4][5][6][7][8][9][10][11][12][13][14].…”

Continuous-wave mirrorless lasing at 221 μm in sodium vapors

“…Minimization of power and atom number density thresholds of the ASE-based lasing is crucially important for possible applications for remote detection. Recently it was shown that there is an optimal power ratio between the components of the bi-chromatic beam for maximizing the efficiency of new field generation by parametric FWM [26]. A detailed study of the optimal conditions minimizing the power and atom number density thresholds is the subject of the forthcoming paper.…”

Saturation and alternate pathways in four-wave mixing in rubidium

“…Frequency up-conversion through parametric fourwave mixing has now been demonstrated in a number of environments, including near resonant cw excitation in rubidium [10][11][12][13] and cesium [14], and pulsed or cw excitation far detuned from the intermediate state [15][16][17][18]. Extensive work has been done to understand the frequency characteristics [19][20][21], observe the infrared emission [22,23], and examine competing pathways and processes [24][25][26].…”