Stimulated emission has been observed on the copper 510.6-, 570.0-, and 578.2-nm, and the gold 627.8-nm transitions at room temperature. Separate discharges are used to produce the metal vapor by sputtering in the presence of a supersonic gas flow, and to excite the metal atoms.
Recently we reported the observation of stimulated emission in atomic copper vapor that is excited by a resonant tunable laser beam.1 One important result obtained in the experiment is that the two upper levels involved in the laser transitions of the atomic copper vapor are collisionally mixed in stimulated emission. This observation is particularly important for studies of high-pressure transverse-discharge copper vapor lasers. We conducted an optical pumping experiment to measure the collisional mixing cross sections (CMCSs) below the threshold of stimulated emission. We observed all four transitions: 2P1/2−2S1/2 (327.4 nm); 2P3/2−2S1/2 (324.8 nm); 2P1/2−2D3/2 (578.2 nm); and 2P3/2−2D5/2 (510.6 nm), when either one of the two levels 2P3/2,1/2 was excited. From the measurements of the intensities of the resonantly excited and sensitized fluorescences, we estimate the CMCSs Q34(2P1/2→2P3/2) and Q43(2P1/2←2P3/2) at 2 × 10−16 and 1.3 × 10-16 cm2 for Cu + Ne collisions, respectively. We also measured the linewidths of the optically pumped green and yellow lasers as a function of the buffer gas pressure and of detuning of the pump frequency. We observe that the linewidths change in an interesting way, which can be explained in terms of the gain narrowing.
We have observed, for the first time to our knowledge, stimulated emission in atomic-copper vapor that is excited by a resonant tunable laser beam. One of the important and interesting results obtained in this experiment is that excitation of the (2)P(1/2) level of the copper atoms generates strong amplified spontaneous emission (ASE) for both(2)P(1/2)-(2)D(3/2) and (2)P(3/2)-(2)D(5/2) transitions. This is the first reported direct experimental evidence observed for collisional mixing between the (2)P(1/2) and (2)P(3/2) levels in a copper-vapor laser. Excitation of the (2)P(3/2) level induces substantially weaker ASE for the (2)P(1/2)-(2)D(3/2) transition. In addition, we observed collision-induced ASE for both transitions over a wide range of detuning of the pump frequency. The preliminary results of the experiment are presented, and the implications of the results for high-pressure copper-vapor lasers are discussed.
A room-temperature beam of krypton atoms in the metastable 5s[3/2]2 level is demonstrated via an optical excitation method. A Kr-discharge lamp is used to produce vacuum ultraviolet photons at 124 nm for the first-step excitation from the ground level 4p6 1S0 to the 5s[3/2]1 level. An 819 nm Ti:sapphire laser is used for the second-step excitation from 5s[3/2]1 to 5s[3/2]2 followed by a spontaneous decay to the 5s[3/2]2 metastable level. A metastable atomic beam with an angular flux density of 3 x 10(14) s(-1) sr(-1) is achieved at the total gas flow rate of 0.01 cm3/s at STP (or 3 x 10(17) at./s). The dependences of the flux on the gas flow rate, laser power, and lamp parameters are investigated.