Search

An optical parametric oscillator operating on a single longitudinal mode of its resonator is described. Using KTP as the nonlinear optical material and a grazing‐incidence‐grating resonator, single‐frequency linewidths of 0.02 cm−1 are achieved. The device, pumped at 532 nm, was tuned over 0.7–0.9 μm (signal branch) and 1.3–2.2 μm (idler branch), and operated with up to 3 mJ of output corresponding to an external photon conversion efficiency of 12%.

The characteristic properties of noncritically phase‐matched second‐harmonic generation in lithium triborate (LiB3O5, LBO) are investigated. Using a LBO crystal grown in our laboratory, we demonstrate that temperature‐tuned noncrictical phase‐matched second‐harmonic generation from 1.025 to 1.253 μm is achieved in a temperature range from 190 to −3 °C. The noncritical phase‐matching temperature for 1.064 μm radiation is found to be 148.0±0.5 °C with a temperature acceptance bandwidth of 3.9 °C cm.

We report the first demonstration of a type II phase‐matched optical parametric oscillator using β‐barium borate (BBO) as the nonlinear optical material. The optical parametric oscillator (OPO) is pumped at 354.7 nm and tuning has been demonstrated over 0.48–0.63 μm and 0.81–1.36 μm. The linewidth of the device, without line narrowing elements, is 0.5–3.0 A, which is dramatically narrower than that of a corresponding type I phase‐matched BBO OPO. Experimentally usable conversion efficiencies of 12% have been achieved.

We report the first measurement of the linear electro‐optic coefficients of crystalline barium metaborate. The largest electro‐optic coefficient r22 was found to be 2.5 pm/V, about four times smaller than the r63 of potassium dihydrogen phosphate (KDP). The dispersion of the electro‐optic coefficient was also measured and found to be in excellent agreement with predicted values using the anharmonic oscillator model. Implications of the result on the point group symmetry of barium metaborate are also discussed.

We report the first successful operation of a β‐BaB2O4 optical parametric oscillator (OPO) tunable in the visible and the near infrared. The OPO was pumped at 354.7 nm and was tunable throughout 0.45–1.68 μm. A maximum total energy conversion efficiency of 9.4% was measured from the OPO containing a 10.5 × 10.5 mm2 × 11.5 mm long, 30° cut β‐BaB2O4 crystal grown in our laboratory. Using the optical parametric luminescence technique, we have measured the 354.7 nm and 266 nm pumped OPO tuning curves (type I and type II) in β‐BaB2O4 throughout the ∼0.3–3.3 μm range. The implication of these results on the validity of the published Sellmeier equations is discussed.

We report the operation of a β‐BaB2O4 singly resonant optical parametric oscillator broadly tunable in the ultraviolet, visible, and infrared regions of the spectrum. This optical parametric oscillator was pumped at 266 nm and was continously tunable throughout 0.33–1.37 μm. A novel cavity design was implemented which has applicability to other parametric oscillators. The oscillation threshold of this device was measured and compared to the calculated result.

We have evaluated barium metaborate ( β‐BaB2O4) for its use in the measurement of ultrashort optical pulses. Using crystals grown in our laboratory, we have found that pulses as short as 50 fs can be measured accurately with a crystal 1.8 mm thick. The advantages of using barium metaborate rather than potassium dihydrogen phosphate (KDP) or ammonium dihydrogen phosphate (ADP) for autocorrelation measurements are discussed.

We report a novel, two‐crystal, walkoff‐compensated optical parametric oscillator design using β‐BaB2O4, which significantly improves the performance of the device. The oscillator is pumped at 354.7 nm and is tunable throughout 0.42–2.3 μm with overall conversion efficiencies as high as 32%. We also report on demonstration of linewidth narrowing in the same β‐BaB2O4 oscillator, obtaining linewidths as narrow as 0.3 A.

Intracavity doubling in β‐BaB2 O4 (BBO) of femtosecond pulses into the ultraviolet with high efficiency is reported. Pulse widths down to 43 fs at a 108 Hz repetition rate and outputs as high as 20 mW per arm of the femtosecond laser on a continuous‐wave basis can be achieved. The ultraviolet pulse widths were determined through detailed cross‐correlation measurements based on sum‐frequency mixing to 210 nm in ultrathin BBO crystals.