Third-harmonic generation of a continuous-wave Ti:Sapphire laser in external resonant cavities

Abstract

An all-solid-state tunable continuous-wave ͑cw͒ laser operating near 272 nm with a bandwidth ⌫ Ϸ3 MHz has been developed. The third harmonic of light from a single-cw Ti:Sapphire laser has been generated using two external enhancement cavities. An output power of 175 mW has been produced, corresponding to an overall conversion efficiency of 8%. © 2003 American Institute of Physics. ͓DOI: 10.1063/1.1584515͔All-solid-state tunable lasers are compact and reliable sources of high-power narrow-band coherent radiation. The applicability of these lasers, however, is limited as they mainly are operational in the red and infrared part of the spectrum. The goal of the present work was to construct an all-solid-state laser system operating at deep-UV wavelengths. Solid-state UV-laser systems producing the fourth harmonic of Nd:YVO 4 are commercially available. These systems are useful for certain applications, however, their wavelength ͑266 nm͒ cannot be tuned or scanned. The development of tunable UV lasers has been reported by the group of Hänsch. 1,2 Bourzeix et al. 3 reported on a fully solidstate UV-laser system, generating the fourth harmonic of a Ti:Sapphire laser. We report on third-harmonic generation of light from a tunable continuous-wave ͑cw͒ Ti:Sapphire ͑Ti:S͒ laser. This is achieved using two steps. First, secondharmonic light is produced using a LBO crystal inside an external enhancement cavity ͑EEC͒. Subsequently, this second-harmonic light is coupled into a second EEC, together with the fundamental light. Here, the sum frequency is generated in a BBO crystal. The power P 3 generated in the sum-frequency process in the BBO crystal is given byHere, P and P 2 are the incident fundamental and secondharmonic power, respectively, and ␥ is the nonlinear coefficient of the process. Resonantly enhancing both wavelengths inside a cavity leads to a high conversion efficiency for the sum-frequency process, expressed bywhere, A and A 2 are the cavity enhancement factors for the fundamental and second-harmonic waves and, now, P and P 2 are the respective powers of the light coupled into the cavity. Sum-frequency generation with two diode lasers was realized by Sayama and Ohtsu.4 Doubly resonant sumfrequency light using two Nd:YAG lasers was generated by Kaneda and Kubota.5 Also, by combining a Ti:S and a diode laser, a narrow-band cw UV source with several tens of milliwatts output power was designed by Fujii et al. 6 Thirdharmonic generation using only a single Ti:S laser was demonstrated by Sayama and Ohtsu, 7 producing 8 nW of deep-UV radiation. In the present work, doubly resonant sum-frequency generation using a single Ti:S laser is demonstrated. The doubly resonant cavity is equipped with two Brewster plates to compensate for the dispersion in the crystal. The result is a compact narrow-band (⌫Ϸ3 MHz), tunable cw laser capable of producing 175 mW of output power in the deep UV. A schematic of the setup is shown in Fig. 1. Narrow-band 817 nm light from a tunable cw Ti:S laser ͑Coherent 899-21͒, which is pumped by a...

6W, 1 kHz linewidth, tunable continuous-wave near-infrared laser

“…The amplitude stabilization with its 250 kHz loop bandwidth allows us to precisely shape light pulses of arbitrary form. This system is ideally suitable for demanding applications such as highorder Bragg diffraction [14] in atom interferometry, or as a basis for a powerful, tunable uv source by frequency multiplication [15].…”

Towards measuring the ionisation and dissociation energies of molecular hydrogen with sub-MHz accuracy

“…This technique has already been applied to produce up to 175 mW and 10 mW cw radiation near 272 nm (Ref. 37) and 227 nm (Ref. 38), respectively.…”

Third-harmonic-generation of a diode laser for quantum control of beryllium ions

“…The dispersion in the BBO crystal must be compensated by other dispersive elements. We use a pair of 1.0-mm-thick fused silica plates [16]. In addition to dispersion compensation, the second plate compensates any displacement from the first plate.…”

“…Our approach is similar to that in Ref. [16], except we seed with a diode laser instead of a Ti:Sapphire laser. The ability for rapid frequency modulation through the diode laser current allows us to use the doubling cavity itself to narrow the laser linewidth considerably and to lock the enhancement cavities with a phase-modulation (Pound-Drever-Hall, PDH) scheme [17] instead of a polarization (Hansch-Couillaud) scheme [18].…”