S. Bourzeix, B. de Beauvoir, F. Nez, F. de Tomasi, L. Julien, and F. Biraben, “Ultraviolet light generation at 205 nm by two frequency doubling steps of a cw titanium-sapphire laser,” Opt. Commun. 133, 239–244 (1997).

H. Tsuchida, “Frequency doubling of tunable Ti:sapphire laser with KNbO_{3} in external cavity,” Jpn. J. Appl. Phys., Part 1 33, 6190–6194 (1994).

S. Bourzeix, M. D. Plimmer, F. Nez, L. Julien, and F. Biraben, “Efficient frequency doubling of a continuous wave titanium:sapphire laser in an external enhancement cavity,” Opt. Commun. 99, 89–94 (1993).

C. S. Adams and A. I. Ferguson, “Tunable narrow linewidth ultra-violet light generation by frequency doubling of a ring Ti:sapphire laser using lithium tri-borate in an external enhancement cavity,” Opt. Commun. 90, 89–94 (1992).

The Hänsch–Couillaud stabilization method is not suitable for spectroscopic applications, especially when a broad wavelength range is required. In carrying out the wavelength tuning measurements we applied the Pound–Drewer–Hall stabilization scheme [see R. W. P. Drewer, J. L. Hall, F. V. Kowalski, J. Hough, G. M. Ford, A. J. Munley, and H. Ward, “Laser phase and frequency stabilization using an optical resonator,” Appl. Phys. B 31, 97–105 (1983)]. The power stability with both of these two techniques remained the same (at least within the limit that we could detect).

T. W. Hänsch and B. Couillaud, “Laser frequency stabilization by polarization spectroscopy of a reflecting reference cavity,” Opt. Commun. 35, 441–444 (1980).

G. D. Boyd and D. A. Kleinman, “Parametric interaction of focused gaussian light beams,” J. Appl. Phys. 39, 3597–3639 (1968).

A. Ashkin, G. D. Boyd, and J. M. Dziendzic, “Resonant optical second harmonic generation and mixing,” IEEE J. Quantum Electron. QE-2, 109–124 (1966).

J. A. Armstrong, N. Bloembergen, J. Ducuing, and P. S. Pershan, “Interactions between light waves in a nonlinear dielectric,” Phys. Rev. 127, 1918–1939 (1962).

P. A. Franken, A. E. Hill, C. W. Peters, and G. Weinreich, “Generation of optical harmonics,” Phys. Rev. Lett. 7, 118–119 (1961).

C. S. Adams and A. I. Ferguson, “Tunable narrow linewidth ultra-violet light generation by frequency doubling of a ring Ti:sapphire laser using lithium tri-borate in an external enhancement cavity,” Opt. Commun. 90, 89–94 (1992).

J. A. Armstrong, N. Bloembergen, J. Ducuing, and P. S. Pershan, “Interactions between light waves in a nonlinear dielectric,” Phys. Rev. 127, 1918–1939 (1962).

A. Ashkin, G. D. Boyd, and J. M. Dziendzic, “Resonant optical second harmonic generation and mixing,” IEEE J. Quantum Electron. QE-2, 109–124 (1966).

S. Bourzeix, B. de Beauvoir, F. Nez, F. de Tomasi, L. Julien, and F. Biraben, “Ultraviolet light generation at 205 nm by two frequency doubling steps of a cw titanium-sapphire laser,” Opt. Commun. 133, 239–244 (1997).

S. Bourzeix, M. D. Plimmer, F. Nez, L. Julien, and F. Biraben, “Efficient frequency doubling of a continuous wave titanium:sapphire laser in an external enhancement cavity,” Opt. Commun. 99, 89–94 (1993).

J. A. Armstrong, N. Bloembergen, J. Ducuing, and P. S. Pershan, “Interactions between light waves in a nonlinear dielectric,” Phys. Rev. 127, 1918–1939 (1962).

S. Bourzeix, B. de Beauvoir, F. Nez, F. de Tomasi, L. Julien, and F. Biraben, “Ultraviolet light generation at 205 nm by two frequency doubling steps of a cw titanium-sapphire laser,” Opt. Commun. 133, 239–244 (1997).

S. Bourzeix, M. D. Plimmer, F. Nez, L. Julien, and F. Biraben, “Efficient frequency doubling of a continuous wave titanium:sapphire laser in an external enhancement cavity,” Opt. Commun. 99, 89–94 (1993).

G. D. Boyd and D. A. Kleinman, “Parametric interaction of focused gaussian light beams,” J. Appl. Phys. 39, 3597–3639 (1968).

A. Ashkin, G. D. Boyd, and J. M. Dziendzic, “Resonant optical second harmonic generation and mixing,” IEEE J. Quantum Electron. QE-2, 109–124 (1966).

T. W. Hänsch and B. Couillaud, “Laser frequency stabilization by polarization spectroscopy of a reflecting reference cavity,” Opt. Commun. 35, 441–444 (1980).

S. Bourzeix, B. de Beauvoir, F. Nez, F. de Tomasi, L. Julien, and F. Biraben, “Ultraviolet light generation at 205 nm by two frequency doubling steps of a cw titanium-sapphire laser,” Opt. Commun. 133, 239–244 (1997).

S. Bourzeix, B. de Beauvoir, F. Nez, F. de Tomasi, L. Julien, and F. Biraben, “Ultraviolet light generation at 205 nm by two frequency doubling steps of a cw titanium-sapphire laser,” Opt. Commun. 133, 239–244 (1997).

The Hänsch–Couillaud stabilization method is not suitable for spectroscopic applications, especially when a broad wavelength range is required. In carrying out the wavelength tuning measurements we applied the Pound–Drewer–Hall stabilization scheme [see R. W. P. Drewer, J. L. Hall, F. V. Kowalski, J. Hough, G. M. Ford, A. J. Munley, and H. Ward, “Laser phase and frequency stabilization using an optical resonator,” Appl. Phys. B 31, 97–105 (1983)]. The power stability with both of these two techniques remained the same (at least within the limit that we could detect).

J. A. Armstrong, N. Bloembergen, J. Ducuing, and P. S. Pershan, “Interactions between light waves in a nonlinear dielectric,” Phys. Rev. 127, 1918–1939 (1962).

A. Ashkin, G. D. Boyd, and J. M. Dziendzic, “Resonant optical second harmonic generation and mixing,” IEEE J. Quantum Electron. QE-2, 109–124 (1966).

C. S. Adams and A. I. Ferguson, “Tunable narrow linewidth ultra-violet light generation by frequency doubling of a ring Ti:sapphire laser using lithium tri-borate in an external enhancement cavity,” Opt. Commun. 90, 89–94 (1992).

The Hänsch–Couillaud stabilization method is not suitable for spectroscopic applications, especially when a broad wavelength range is required. In carrying out the wavelength tuning measurements we applied the Pound–Drewer–Hall stabilization scheme [see R. W. P. Drewer, J. L. Hall, F. V. Kowalski, J. Hough, G. M. Ford, A. J. Munley, and H. Ward, “Laser phase and frequency stabilization using an optical resonator,” Appl. Phys. B 31, 97–105 (1983)]. The power stability with both of these two techniques remained the same (at least within the limit that we could detect).

P. A. Franken, A. E. Hill, C. W. Peters, and G. Weinreich, “Generation of optical harmonics,” Phys. Rev. Lett. 7, 118–119 (1961).

The Hänsch–Couillaud stabilization method is not suitable for spectroscopic applications, especially when a broad wavelength range is required. In carrying out the wavelength tuning measurements we applied the Pound–Drewer–Hall stabilization scheme [see R. W. P. Drewer, J. L. Hall, F. V. Kowalski, J. Hough, G. M. Ford, A. J. Munley, and H. Ward, “Laser phase and frequency stabilization using an optical resonator,” Appl. Phys. B 31, 97–105 (1983)]. The power stability with both of these two techniques remained the same (at least within the limit that we could detect).

T. W. Hänsch and B. Couillaud, “Laser frequency stabilization by polarization spectroscopy of a reflecting reference cavity,” Opt. Commun. 35, 441–444 (1980).

P. A. Franken, A. E. Hill, C. W. Peters, and G. Weinreich, “Generation of optical harmonics,” Phys. Rev. Lett. 7, 118–119 (1961).

The Hänsch–Couillaud stabilization method is not suitable for spectroscopic applications, especially when a broad wavelength range is required. In carrying out the wavelength tuning measurements we applied the Pound–Drewer–Hall stabilization scheme [see R. W. P. Drewer, J. L. Hall, F. V. Kowalski, J. Hough, G. M. Ford, A. J. Munley, and H. Ward, “Laser phase and frequency stabilization using an optical resonator,” Appl. Phys. B 31, 97–105 (1983)]. The power stability with both of these two techniques remained the same (at least within the limit that we could detect).

S. Bourzeix, B. de Beauvoir, F. Nez, F. de Tomasi, L. Julien, and F. Biraben, “Ultraviolet light generation at 205 nm by two frequency doubling steps of a cw titanium-sapphire laser,” Opt. Commun. 133, 239–244 (1997).

S. Bourzeix, M. D. Plimmer, F. Nez, L. Julien, and F. Biraben, “Efficient frequency doubling of a continuous wave titanium:sapphire laser in an external enhancement cavity,” Opt. Commun. 99, 89–94 (1993).

G. D. Boyd and D. A. Kleinman, “Parametric interaction of focused gaussian light beams,” J. Appl. Phys. 39, 3597–3639 (1968).

The Hänsch–Couillaud stabilization method is not suitable for spectroscopic applications, especially when a broad wavelength range is required. In carrying out the wavelength tuning measurements we applied the Pound–Drewer–Hall stabilization scheme [see R. W. P. Drewer, J. L. Hall, F. V. Kowalski, J. Hough, G. M. Ford, A. J. Munley, and H. Ward, “Laser phase and frequency stabilization using an optical resonator,” Appl. Phys. B 31, 97–105 (1983)]. The power stability with both of these two techniques remained the same (at least within the limit that we could detect).

The Hänsch–Couillaud stabilization method is not suitable for spectroscopic applications, especially when a broad wavelength range is required. In carrying out the wavelength tuning measurements we applied the Pound–Drewer–Hall stabilization scheme [see R. W. P. Drewer, J. L. Hall, F. V. Kowalski, J. Hough, G. M. Ford, A. J. Munley, and H. Ward, “Laser phase and frequency stabilization using an optical resonator,” Appl. Phys. B 31, 97–105 (1983)]. The power stability with both of these two techniques remained the same (at least within the limit that we could detect).

S. Bourzeix, B. de Beauvoir, F. Nez, F. de Tomasi, L. Julien, and F. Biraben, “Ultraviolet light generation at 205 nm by two frequency doubling steps of a cw titanium-sapphire laser,” Opt. Commun. 133, 239–244 (1997).

S. Bourzeix, M. D. Plimmer, F. Nez, L. Julien, and F. Biraben, “Efficient frequency doubling of a continuous wave titanium:sapphire laser in an external enhancement cavity,” Opt. Commun. 99, 89–94 (1993).

J. A. Armstrong, N. Bloembergen, J. Ducuing, and P. S. Pershan, “Interactions between light waves in a nonlinear dielectric,” Phys. Rev. 127, 1918–1939 (1962).

P. A. Franken, A. E. Hill, C. W. Peters, and G. Weinreich, “Generation of optical harmonics,” Phys. Rev. Lett. 7, 118–119 (1961).

S. Bourzeix, M. D. Plimmer, F. Nez, L. Julien, and F. Biraben, “Efficient frequency doubling of a continuous wave titanium:sapphire laser in an external enhancement cavity,” Opt. Commun. 99, 89–94 (1993).

H. Tsuchida, “Frequency doubling of tunable Ti:sapphire laser with KNbO_{3} in external cavity,” Jpn. J. Appl. Phys., Part 1 33, 6190–6194 (1994).

The Hänsch–Couillaud stabilization method is not suitable for spectroscopic applications, especially when a broad wavelength range is required. In carrying out the wavelength tuning measurements we applied the Pound–Drewer–Hall stabilization scheme [see R. W. P. Drewer, J. L. Hall, F. V. Kowalski, J. Hough, G. M. Ford, A. J. Munley, and H. Ward, “Laser phase and frequency stabilization using an optical resonator,” Appl. Phys. B 31, 97–105 (1983)]. The power stability with both of these two techniques remained the same (at least within the limit that we could detect).

P. A. Franken, A. E. Hill, C. W. Peters, and G. Weinreich, “Generation of optical harmonics,” Phys. Rev. Lett. 7, 118–119 (1961).

The Hänsch–Couillaud stabilization method is not suitable for spectroscopic applications, especially when a broad wavelength range is required. In carrying out the wavelength tuning measurements we applied the Pound–Drewer–Hall stabilization scheme [see R. W. P. Drewer, J. L. Hall, F. V. Kowalski, J. Hough, G. M. Ford, A. J. Munley, and H. Ward, “Laser phase and frequency stabilization using an optical resonator,” Appl. Phys. B 31, 97–105 (1983)]. The power stability with both of these two techniques remained the same (at least within the limit that we could detect).

A. Ashkin, G. D. Boyd, and J. M. Dziendzic, “Resonant optical second harmonic generation and mixing,” IEEE J. Quantum Electron. QE-2, 109–124 (1966).

G. D. Boyd and D. A. Kleinman, “Parametric interaction of focused gaussian light beams,” J. Appl. Phys. 39, 3597–3639 (1968).

H. Tsuchida, “Frequency doubling of tunable Ti:sapphire laser with KNbO_{3} in external cavity,” Jpn. J. Appl. Phys., Part 1 33, 6190–6194 (1994).

S. Bourzeix, B. de Beauvoir, F. Nez, F. de Tomasi, L. Julien, and F. Biraben, “Ultraviolet light generation at 205 nm by two frequency doubling steps of a cw titanium-sapphire laser,” Opt. Commun. 133, 239–244 (1997).

T. W. Hänsch and B. Couillaud, “Laser frequency stabilization by polarization spectroscopy of a reflecting reference cavity,” Opt. Commun. 35, 441–444 (1980).

C. S. Adams and A. I. Ferguson, “Tunable narrow linewidth ultra-violet light generation by frequency doubling of a ring Ti:sapphire laser using lithium tri-borate in an external enhancement cavity,” Opt. Commun. 90, 89–94 (1992).

S. Bourzeix, M. D. Plimmer, F. Nez, L. Julien, and F. Biraben, “Efficient frequency doubling of a continuous wave titanium:sapphire laser in an external enhancement cavity,” Opt. Commun. 99, 89–94 (1993).

J. A. Armstrong, N. Bloembergen, J. Ducuing, and P. S. Pershan, “Interactions between light waves in a nonlinear dielectric,” Phys. Rev. 127, 1918–1939 (1962).

P. A. Franken, A. E. Hill, C. W. Peters, and G. Weinreich, “Generation of optical harmonics,” Phys. Rev. Lett. 7, 118–119 (1961).

To get a continuous scan range larger than ±3 GHz, one could mount a Brewster plate into the cavity. It could then take care of slow variations while the PZT-driven mirror would correct for higher frequencies.

Throughout this paper we follow the usual convention that both the reflectivity and the transmissivity are related to the optical intensity (power).

Absolute power values are uncertain to ±2.5% of the stated value because of uncertainty in detector calibration.