Daoqun Deng

Highly efficient ultraviolet generation at 355 nm in LiB 3 O 5

Highly efficient generation of UV radiation at 355 nm has been achieved in a LiB(3)O(5) crystal through the frequency mixing of the fundamental and second-harmonic radiation of a Nd:YAG laser. An energy conversion efficiency of 60% has been obtained under the experimental conditions described here. Thus the usefulness of LiB(3)O(5) for frequency-conversion applications is demonstrated.

Generation of tunable coherent vacuum ultraviolet radiation in LiB3O5 crystal

Generation of tunable vacuum ultraviolet radiation down to 187.7 nm has been achieved by means of type-I sum-frequency mixing with the outputs of the fifth harmonic of a Nd:YAG laser and on optical parametric oscillator (OPO) pumped by the second harmonic of the same Nd:YAG laser in a LiB3O5 crystal. A peak power as high as 67 kW with an average power of 2 mW is obtained at 191.4 nm. Furthermore, a suitable modification has been made on the Sellmeiers equations of the crystal so that the equations can be basically used in wide range from vacuum ultraviolet to infrared.

Highly efficient visible and infrared β‐BaB2O4 optical parametric oscillator with pump reflection

We report the successful operation of a highly efficient visible and near‐infrared optical parametric oscillator (OPO) that uses β‐BaB2O4 as the nonlinear medium and is pumped at 354.7 nm. An energy conversion efficiency of 41% corresponding to a quantum conversion efficiency as high as 57% has been achieved in a 10‐mm‐long crystal. Pump depletion is estimated to be 70% or so. This OPO can generate an average output power to 507 mW at 490 nm and can be continuously tuned from 415 to 2411 nm. The reverse frequency conversion process has also been observed in the OPO. The reason for its high efficiency is discussed.

Visible optical parametric oscillation in LiB3O5

The successful operation of a visible optical parametric oscillator (OPO) using a LiB3O5 crystal as the nonlinear element is reported. An energy conversion efficiency as high as 22% for a signal wave has been obtained in a 15.9‐mm‐long crystal. This OPO can generate visible output energy of 2.7 mJ and be continuously tuned from 435 to 1922 nm.

Retracing behavior of the phase‐matching angle of nonlinear crystals in optical parametric oscillators

The retracing behavior of the phase‐matching angle (RBPA) of many nonlinear optical crystals in optical parametric oscillators (OPO) is reported here. The wavelength range of the pump wave and the tuning angle range over which RBPA can occur are obtained. Furthermore, the generality of this novel and interesting phenomenon is successfully explained by theoretical analysis. We point out that RBPA exists generally in both type I and type II OPO’s by using either uniaxial or biaxial crystals.

The compound cavity optical parametric oscillator: theory and experiment

We present the time dynamics of a compound-cavity optical parametric oscillator (OPO) using a mathematical model for the modes under the gain profile of the oscillator which accounts for pump depletion and the cavity-Q factors. The computational results show that this type of cavity is superior in that its threshold is lower than that of a simple narrow-band cavity with dispersive elements and its efficiency is increased, while its narrow linewidth remains nearly the same across the tunable range of the nonlinear crystals used. A diagram illustrating the operation state of a compound-cavity OPO is presented, which is applicable to the simple narrow-band cavity, simple broad-band cavity, compound cavity, and traveling-wave amplification. The theoretical results are compared to the experimental data from a compound-cavity OPO using a grazing-incidence prism and grating as dispersive elements.

Multiwavelength optical parametric amplification with angle-tuned lithium triborate

The retracing behavior of the phase matching in optical parametric processes with angle-tuned LiB3O5 crystals has been investigated. The simultaneous generation of two pairs of parametric beams and a novel multiwavelength interaction phenomenon have been observed and analyzed. The design and performance of a picosecond multiwavelength optical parametric amplifier with three angle-tuned lithium triborate crystals is described. As much as 2.34 mJ/pulse of output, corresponding to a conversion efficiency of 26%, has been obtained.

Optical parametric system with a compound cavity and a grazing-incidence prism

We report a new type of optical parametric oscillator cavity, i.e., a compound cavity with a grazing-incidence prism. The optical parametric oscillator is based on a β-BaB2O4 crystal and is pumped by the third harmonic of a Nd:YAG laser. Compared with the grazing-incidence-prism optical parametric oscillator (narrow-band cavity), the compound cavity has the same linewidth, whereas its threshold is only half as high and its external efficiency is an order of magnitude greater.

Narrow Linewidth, Nanosecond Pulsed Optical Parametric Oscillator with a Compound Cavity

We report a new type of optical parametric oscillator (OPO) cavity, i.e., a compound cavity OPO. Both the numerical simulation and experimental results show that this type of cavity is superior, in that its threshold is lower than that of a simple narrow-band cavity with dispersive elements, and its external efficiency is increased while its narrow linewidth remains nearly the same across the tunable range of the nonlinear crystals used.

Compound cavity optical parametric oscillator

We report a new type of optical parametric oscillator (OPO) cavity, i.e. a compound cavity OPO, and present its time dynamics based on a mathematical model. Both the numerical simulation and experimental results show that this type of cavity is superior in that its threshold is lower than that of a simple narrow-band cavity with dispersive elements, and its external efficiency is increased while its narrow linewidth remains nearly the same across the tunable range of the nonlinear crystals used.