Beam Reflection by Transversely Chirped Volume Bragg Grating

Reflective uniform volume Bragg gratings (VBGs) in photo-thermo-refractive (PTR) glass are used as narrow-band output couplers in high-power lasers with different gain media [1]. VBGs with longitudinally chirped grating period are used for stretching and compression of ultrashort laser pulses in well established chirped pulse amplification schemes [2]. Here we discuss reflective VBGs with chirp of the resonant Bragg wavelength in transverse direction as it is presented in Figure 1a. Such VBGs have uniform refractive index modulation along the longitudinal direction of reflection at any particular transverse point of incidence. These transversely chirped volume Bragg gratings (TCVBGs) have been already implemented experimentally in different laser systems. One particular TCVBG has been used for locking and tuning of nanosecond optical parametric oscillator as shown in [3]. In another work, the wavelength tunability of narrow line fiber laser has been realized using similar TCVBG [4]. In both experimental realizations the results have demonstrated fulfillment of the designed goals.