Femtosecond-Laser-Inscribed BiB$_{3}$O$_{6}$ Nonlinear Cladding Waveguide for Second-Harmonic Generation

Abstract

We report on the fabrication of a nonlinear cladding waveguide in BiB 3 O 6 crystal by using femtosecond laser inscription. The waveguide (with a nearly circular cross section of 150 m diameter) shows good guiding properties in two transverse polarizations. The guided-wave secondharmonic generation (SHG) at 532 nm green light has been realized under CW and pulsed wave pump at 1064 nm, based on the Type I birefringent phase matching configuration. The conversion efficiencies for CW and pulsed green laser SHG are 0.083 and 25%, respectively.

Control of the properties of micro-structured waveguides in lithium niobate crystal

“…Depressed-cladding WGs have been demonstrated to achieve light propagation with good mode confinement at different wavelengths, and low propagation losses as compared with directly written, single-track WGs [5,6,10,17,19]. It has also been proved that depressed-cladding WGs in nonlinear crystals can achieve enhanced-efficiency secondharmonic generation as compared with stress-induced WGs [20,21].…”

Second Harmonic Generation of Violet Light in Femtosecond-Laser-Inscribed BiB3O6Cladding Waveguides

“…The cladding structure was produced by using fs-laser-inscription (details on the experiment can be found in [6]). The nonlinear performance of the waveguide was characterized by utilizing a typical end-face coupling system.…”

“…The second harmonic generation (SHG) from visible till UV light band can be achieved in BiB 3 O 6 via birefringent phase matching (PM). We have reported the fabrication of cladding waveguides in this crystal and realized the 1064→532 nm SHG [6]. In this work, we report on the SHG features of the BiB 3 O 6 cladding waveguide for 800→400 nm SHG of violet light.…”

Efficient lasing in Nd:GdVO4depressed cladding waveguides produced by femtosecond laser writing

“…The circular depressed double cladding waveguides were produced by using the laser facility of the Universidad de Salamanca, Spain, in which system a Ti:Sapphire regenerative amplifier (Spitfire, Spectra Physics, USA) was used as laser source. It delivered linearly-polarized pulses of 120 fs and 795 nm central wavelength at 1 kHz repetition rate as in previous works [16,[20][21][22][23]. The maximum available pulse energy was 1 mJ but it was reduced with a calibrated neutral density filter placed after a half-wave plate and a linear polarizer, in order to get a fine control of the incident energy.…”

“…More interestingly, the Type III waveguides may support balanced guided modes along both TE and TM polarizations, which is one of the unique features of depressed cladding waveguides. As of yet, Type III waveguides have already been fabricated in a number of optical materials, e.g., Nd:YAG single crystals and ceramics [13,19,20], BiB 3 O 6 [21], Nd:YVO 4 [22], Nd:…”