Laser and Particle Beams


SPECIAL ISSUEECLIM '98 PAPERS

Frequency doubling of multi-terawatt picosecond pulses


D.  NEELY a1, C.N.  DANSON a1, R.  ALLOTT a1, F.  AMIRANOFF a3, J.L.  COLLIER a1, A.E.  DANGOR a2, C.B.  EDWARDS a1, P.  FLINTOFF a1, P.  HATTON a1, M.  HARMAN a1, M.H.R.  HUTCHINSON a1, Z.  NAJMUDIN a2, D.A.  PEPLER a1, I.N.  ROSS a1, M.  SALVATI a2 and T.  WINSTONE a1
a1 CLRC Rutherford Appleton Laboratory, Chilton, Didcot, Oxon, OX11 0QX, UK
a2 Imperial College, Prince Consort Road, London, UK
a3 LULI, Ecole Polytechnique, Palaiseau, France

Abstract

The frequency-doubling efficiency and resultant focal spot quality of a large aperture (140 × 89 mm) subpicosecond, chirped pulse amplified (CPA) 1054-nm beam for laser–matter interaction studies has been investigated using the Vulcan Nd:glass laser system (Danson et al. 1998). The effect of B-integral on the CPA beam quality was studied and is shown not to be the dominant cause of the observed frequency-doubled beam break-up. Conversion efficiency tests were carried out on small aperture KDP (type 1) crystals at a range of incident intensities up to 3 × 1011 W/cm2 giving the optimum crystal thickness for pulses in the 0.3–3 ps region. A large-aperture frequency-doubled beam was commissioned and delivered pulses of over 10 TW onto target for an electron acceleration experiment.

(Received July 9 1998)
(Accepted December 2 1998)