Highly Efficient Mid-Infrared Generation from Low-Power Single-Frequency Fiber Laser Using Phase-Matched Intracavity Difference Frequency Mixing

Abstract

In this paper, we demonstrated efficient mid-infrared generation using a low-power 1064 nm single-frequency (SF) fiber laser based on phase-matched intracavity difference frequency generation (DFG) in a continuous-wave (CW) periodically poled lithium niobate (PPLN)-based optical parametric oscillator (OPO). This is the first time that the frequency down conversion of a low-power SF light source has been achieved using intracavity difference frequency mixing. A high power 1018 nm fiber laser was firstly used for building the parametric oscillation and providing the high power resonant signal wave. To realize an efficient DFG process between the SF pump wave and the intracavity signal wave, the temperature of periodically poled lithium niobate (PPLN) crystal was properly adjusted to satisfy the phase-matching conditions. Finally, the low-power 1064 nm SF pump wave was successfully converted to a 3.7 μm mid-infrared wave with a conversion efficiency of 21.6%. The conversion efficiency, to the best of our knowledge, is the highest for SF lasers in DFG processes. Meanwhile, taking advantage of SF laser pumping, a narrow linewidth of 271 pm (5.9 GHz) in the mid-infrared region was achieved without adding any etalons or devices in the cavity.

Propagation and Transformation of Vortexes in Linear and Nonlinear Radio-Photon Systems

“…The results of the process simulation show the asymptotic behavior of the lasing efficiency index as a function of the length of the nonlinear medium, an increase in the lasing efficiency with an increase in the frequency difference that determines the frequency of the radio vortex beam, and also the extreme behavior of the efficiency exponent on the waist radius of the pump laser beams. It should be noted that the use of Bessel-Gauss beams with fractional topological charge may turn out to be a promising direction of work in this area [9,18].…”

“…PPLN crystals are also used to generate infrared radiation with a wavelength of the order of several microns [18]. In addition to PPLN/PPLT crystals, KTP crystals can also be used for SHG of Laguerre-Gauss modes [19].…”

Broadband, Continuous-Wave, Mid-Infrared Generation Based on ASE Fiber Source

“…In 2018, Wang Peng et al used intracavity DFG in PPLN OPO to improve the conversion efficiency of 1080 nm lasers in the frequency down-conversion process, a new solution to generate CW mid-infrared lasers with low pump power [26]. Moreover, in the follow-up research [27], the intracavity DFG was further improved and optimized.…”

Propagation and Transformation of Vortexes in Linear and Nonlinear Radio-photon Systems

“…Article [17] experimentally shows the possibility of generating the second harmonic by plas-mons, and the topological charge doubles as the frequency is doubled. PPLN crystals are also used to generate infrared radiation with a wavelength of the order of several microns [18]. In addition to PPLN / PPLT crystals, KTP crystals can also be used for SHG of Laguerre -Gauss modes [19].…”