Presentation on theme: "Self-Guided Operation of Green-Pumped Singly Resonant CW OPO based on Bulk MgO:PPLN In-ho Bae, 1 Han Seb Moon, 1 Sebastian Zaske, 2 Christoph Becher, 2."— Presentation transcript:
Self-Guided Operation of Green-Pumped Singly Resonant CW OPO based on Bulk MgO:PPLN In-ho Bae, 1 Han Seb Moon, 1 Sebastian Zaske, 2 Christoph Becher, 2 Seung Kwan Kim, 3 Seung-Nam Park, 3 and Dong-Hoon Lee 3,* 1 Department of Physics, Pusan National University, Busan , Rep. Korea 2 Universität des Saarlandes, Fachrichtung 7.3 (Technische Physik), Saarbrücken, Germany 3 Division of Physical Metrology, Korea Research Institute of Standards and Science (KRISS), Daejeon , Rep. Korea *
Introduction Continuous-wave (CW) optical parametric oscillators (OPOs) based on quasi-phase-matching (QPM) broad wavelength coverage wide single-frequency tuning range correlations between the signal and idler output beams thermal lensing and de-phasing limitation of parametric efficiency, spatial mode quality, spectral tuning property, and stability of CW OPOs Nonlinear crystal Cavity design
Singly resonant OPO setup HR : high reflectivity HWP : half-wave plate ISO : isolator A : aperture OSA : optical spectrum analyzer BD : beam dump MgO: PPLN Oven Translator XY stage Polling period Λ 7.2 μm, 7.4 μm, 7.6 μm, 7.8 μm Pump : 532 nm Signal : 770~890 nm Idler : 1330~1680 nm
Wavelength tuning curve Signal : 770~890 nm Idler : 1330~1680 nm We fitted experimental results by using Sellmeier equations for 5% MgO-doped congruent PPLN in Ref. .  Gayer et. al. Appl. Phys. B 91, 343–348.
Thermal wave-guide effect ▶ Resonance frequency of the TEM nmq Mode ▶ Transverse mode spacing ▶ Resonator g parameters & Stability condition Laser Resonator Stability Diagram R = 50 mm, limited cavity length : 100 mm L > 100 mm unstable cavity In our case, unstable cavity is above 122 mm.
Output power characteristics
98 mm Continuous tuning range mm mm
Thermal absorption time Leff 93.4 mmLeff mm
Spatial mode profile Leff 98 mm Leff mm Leff mm
Pump mode profile beforeafter
Summary We operated Self-Guided singly resonant CW OPOs that was assisted by thermal wave guide effect. We got 400 ~ 600 MHz and 600 ~ 800 MHz for continuous tuning range under the stable and unstable cavity condition, respectively. The spatial mode of the CW OPOs were improved by thermal effect in unstable cavity and the Gaussian mode profile was achieve at the maximum cavity length. In the near future, CW – OPOs with unstable cavity method will be used to find atomic transition spectrum though optimization and stabilization of continuous tuning range.