A titanium sapphire crystal is used as a "gain material" in a tunable laser that can lase between 700nm and 1000 nm. Typically, it is pumped by a green laser (532nm). As shown below, the green pump laser passes through the dichroic mirror (designed to reflect the 700-1000 nm light, and transmit the 532 nm light). The green pump laser enters the laser crystal where it is absorbed. The concentration of titanium atoms in the sapphire (A1202) host controls the crystal's absorption coefficient a. For a 0.1% (by weight) titanium composition, the absorption coefficient at 532 nm is a =1.5/cm. If you want the laser crystal to absorb 99% of the pump laser as it passes through one time, what length crystal (L), should you order? Output coupler Dichroic mirror (leaky mirror) Length L 523 nm pump laser Ti Sapphire