Generation of sub‐terahertz repetition rates from a monolithic self‐mode‐locked laser coupled with an external Fabry‐Perot cavity

Abstract

A novel scheme to multiply the repetition rate of a monolithic self-mode-locked laser for generating sub-terahertz pulse sources is successfully demonstrated. A coated Yb:KGW crystal is designed to achieve a self-mode-locked operation at a repetition rate of 24 GHz with an average output power exceeding 1.0 W at a pump power of 4.8 W. A partially reflective mirror is utilized to combine with the output surface of the gain medium to constitute an external Fabry-Perot cavity. It is theoretically and experimentally verified that adjusting the external cavity length to satisfy the commensurate condition can lead to the frequency spacing to be various order harmonics of the mode spacing of the monolithic cavity. The maximum pulse repetition rate of the laser output can be up to 216 GHz and the pulse duration is as short as 330 fs. More importantly, the overall characteristics of the first-order temporal autocorrelation traces obtained by sequentially scanning the external cavity.length display an intriguing phenomenon of temporally fractional revivals, similar to the feature of spatial Talbot revivals.

Monolithic dual-polarization self-mode-locked Nd:YAG 946-nm lasers: controlling beat frequency and observation of temporal chaos

“…Both theoretical and experimental results confirm that an increase in the longitudinal mode spacing is effectively beneficial to the SML operation [24][25][26]. Consequently, the monolithic resonator with large mode spacing is particularly suitable for the SML operation [25][26][27][28]. In the early stages, monolithic or bonded cavities were often used in developing the continuous-wave [29][30][31] and passively Q-switched lasers [32][33][34][35] due to the advantage of mechanical stability, compact, and alignment-free manufacturing.…”

Broad expansion of optical frequency combs by self-Raman scattering in coupled-cavity self-mode-locked monolithic lasers

“…The advent of diode-pumped laser technology and fast real-time detection systems have opened up a number of new developments on the SML operation [13][14][15][16][17][18][19][20]. In addition to the Kerr lens effect, the mechanism for the SML in short linear cavities is mainly attributed to the large mode spacing to prevent the mode competition [14,20]. The SML pulse train with the repetition rate of several tens of GHz was successfully demonstrated in the monolithic Yb:KGW crystal laser [14].…”

“…The SML pulse train with the repetition rate of several tens of GHz was successfully demonstrated in the monolithic Yb:KGW crystal laser [14]. With the ML monolithic laser, a coupled cavity scheme was further used to multiply the repetition rate up to sub-THz [20].…”