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RISTRA Theory

The RISTRA is an image-rotating nanosecond optical parametric oscillator. The RISTRA uses a "Rotated-Image, Singly resonant, Twisted-RectAngle" cavity. RISTRA's nonplanar twisted-rectangle cavity is illustrated in Figure 1. The angles of the mirrors are selected to introduce a 90° rotation of the resonated signal beam on each pass of the cavity. Many such rotations, along with angle critical birefringent phase matching, produce a highly symmetric beam profile of good quality.

 

RISTRA Nonplanar Cavity

Figure 1: RISTRA's twisted-rectangle, nonplanar cavity. From A. V. Smith and D. J. Armstrong, “Nanosecond optical parametric oscillator with 90° image rotation: design and performance,” J. Opt. Soc. Am. B 19, 1801-1814 (2002).

 

The following publications present the theory of image-rotating OPOs in more detail:
  1. A. V. Smith and D. J. Armstrong, “Nanosecond optical parametric oscillator with 90° image rotation: design and performance,” J. Opt. Soc. Am. B 19, 1801-1814 (2002).
  2. D. J. Armstrong and A. V. Smith, “Demonstration of improved beam quality in an image-rotating optical parametric oscillator,” Opt. Lett. 27, 40-42 (2002).
  3. A. V. Smith and M. S. Bowers, “Image-rotating cavity designs for improved beam quality in nanosecond optical parametric oscillators,” J. Opt. Soc. Am. B 18, 706-713 (2001).