Patent ID: 7508847

Claim:
A rare earth ion ultrashort laser source comprising: a resonant cavity ( 1 ) having a first output face ( 2 ) partially reflecting and a second reflecting face ( 3 ), a first active material ( 4 ) placed inside the resonant cavity said first active material having a saturation fluency greater than 3 J/cm 2 and receiving a pump luminous flux ( 5 ), said pump luminous flux being transmitted by a first solid laser pump source ( 7 ), said first solid laser pump source transmitting luminous pulses having an energy E L , wherein: the resonant cavity ( 1 ) exhibits a length of optical path travelled by said luminous pulses greater than 7.5 m so that the pulsed energy E L is greater than 100 nJ, said optical path including at least one passage in said first active material ( 4 ), the ultrashort laser source comprises a member for lengthening the resonant cavity ( 1 ) thereby extending the length of the optical path travelled by said luminous pulses in the resonant cavity ( 1 ) of said ultrashort laser source, the resonant cavity ( 1 ) comprises an ABCD propagation matrix that is close to a unit matrix so that the features of the luminous pulses going back and forth in the resonant cavity ( 1 ) remain unchanged.