Highly efficient visible urea optical parametric oscillator pumped by a XeCl excimer laser

Area of Science:

• Nonlinear Optics
• Laser Physics
• Materials Science

Background:

• Optical parametric oscillators (OPOs) are crucial for generating tunable laser light.
• Urea is an organic nonlinear crystal with potential for optical applications.
• Pulsed laser systems require efficient nonlinear media for frequency conversion.

Purpose of the Study:

• To demonstrate the successful operation of a visible optical parametric oscillator (OPO) using urea as the nonlinear medium.
• To characterize the tuning range and conversion efficiency of the urea-based OPO.
• To investigate the impact of crystal properties on OPO performance.

Main Methods:

• Utilized an injection-seeded pulsed XeCl excimer laser (308 nm) as the pump source.
• Employed urea as the nonlinear crystal in a singly resonant optical parametric oscillator.
• Characterized the output radiation's tuning range (537–720 nm) and conversion efficiency.

Main Results:

• Achieved continuous tunability of the OPO output from 537 nm to 720 nm.
• Obtained a maximum conversion efficiency of 37% at 90-degree phase matching with a 15-mm urea crystal.
• Analyzed the effects of crystal double refraction and beam walk-off on efficiency.

Conclusions:

• Urea is a viable nonlinear medium for efficient visible optical parametric oscillation.
• The demonstrated OPO offers a wide tuning range and high conversion efficiency.
• Further studies can optimize OPO performance by managing crystal properties and beam interactions.