Influence of Cr4+ ion concentration on cw operation of forsterite laser and its relation to thermal problems

Pulse-width-tunable 07 W mode-locked Cr: forsterite laser

“…The laser crystal, cooled down to 278 K, is located between a pair of 100 mm curvature-radius focusing mirrors. In agreement with the earlier studies [11,13], an increase in the temperature of the forsterite crystal in our system reduced the lifetime of the upper laser state and decreased the quantum yield of fluorescence. A semiconductor saturable-absorber mirror (SESAM) with a response time of 2 ps and modulation depth of 0.025 is used as a rear reflector of the laser cavity.…”

A sub-100fs self-starting Cr:forsterite laser generating 14W output power

“…The laser resonator employed a conventional Z-fold linear cavity. In order to achieve high output performance at high pump power, we used a pump lens with an 155mm focal length and used curve mirrors with an 150mm radius of curvature, which is longer than the previous works [31][32][33][34][35][36][37]40,[42][43][44][45]. It is to reduce the thermal gradient inside the crystal at a high pumping level.…”

“…After the first lasing operation of Cr:forsterite in 1988 [30], great strides were made in optimizing and improving its performance [31][32][33][34][35][36][37][38][39][40][41][42][43][44][45]. A record-high 2.8W in cryogenic operation [31] and 1.1W at 288K [32] were reported in CW generation.…”

“…For the potential applications without complicated light source maintenance, stable generation and high output power delivered directly from a single cavity is required. Comparing with the leading material in the field of femtosecond lasers, Ti:sapphire, the thermal conductivity, the excited-state absorption, and high temperature sensitivity of the Cr:forsterite crystal hampered the output power of the forsterite laser [35][36][37]. Nevertheless, without using complex cavity dump [38] or regenerative amplifier scheme [39], a long cavity with high pulse energy (~17 nJ) and a repetition rate of 26.5MHz [40] was previously achieved by employing a telescope.…”

Dispersion Compensation Devices

“…This is particularly good for Cr:forsterite because its low thermal conductivity does not allow to use a thin crystal with high doping density. It is reasonable to use a relatively long crystal to ease the thermal problem (Ivanov et al 1995). This is in contrast to the case of Ti:sapphire lasers where neither of the conditions can be fulfilled by available prism materials so that thin crystal is the only choice.…”