The rotational and hyperfine spectrum of the X 1 Σ + → B 3 Π1 transition in TlF molecules was measured using laser-induced fluorescence from both a thermal and a cryogenic molecular beam. Rotational and hyperfine constants for the B state are obtained. The large magnetic hyperfine interaction of the Tl nuclear spin leads to significant mixing of the lowest B state rotational levels. Updated, more precise measurements of the B → X vibrational branching fractions are also presented. The combined rovibrational branching fractions allow for the prediction of the number of photons that can be scattered in a given TlF optical cycling scheme.

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We report a simple tunable master-slave laser injection-lock scheme for atomic physics experiments. Seed light from an external cavity diode laser is injected into a high-power fiber-pigtailed diode laser via a fiber optic circulator. High-power outputs (up to ∼600 mW) at the injected frequency have been obtained in a singlemode fiber with tuning over a wide wavelength range (∼15 nm). The scheme is simpler and more cost-effective than the traditional scheme of free-space injectionlocking. PACS numbers: Valid PACS appear hereTunable single frequency external cavity diode lasers (ECDLs) are widely used in atomic physics experiments. 1 Typically, 100 mW of output power can be obtained from an ECDL. When higher powers are required, master-slave setups based on injection-locking are frequently used to reach higher power output while maintaining the tuning and linewidth characteristics of the ECDL. In these systems, typically seed light from a master laser is coupled via free space into a slave laser, with the combination of a Faraday rotator and a polarizing beamsplitter acting to separate the amplified beam from the injected beam. 2 Such free-space injection-locking, however, is often susceptible to unlocking of the slave laser from the injected frequency. The success of the injection locking depends on the mode matching between the seed beam and the slave diode, on the in-coupled seed power, and on the matching between the seed frequency and the internal cavity resonance of the seed laser. Changes in the operating conditions over time can result in unreliable locking of the slave diode. An interesting and practical approach to circumvent such unlocking has been reported recently. 3 Alternatively, tapered amplifiers (TAs) can also be used to boost the available power. The power available from a TA depends on the wavelength, and is quite high at a few commonly-used wavelengths such as 850 nm. However, the range of wavelengths accessible with TAs is limited, their cost is substantial, and they often require free-space coupling as well. In addition, the beam quality obtained from a TA is often poor, leading to a low coupling efficiency of the TA output beam to a single-mode optical fiber.In this paper, we demonstrate a simple scheme to obtain moderate powers, up to 600 mW at 980 nm, of tunable single-frequency laser light directly in an optical fiber. Our scheme uses a fiber-pigtailed laser diode as a slave laser, injection-locked by a seed from an ECDL via a fiber optic circulator. Injection-locking via a fiber optic circulator has been demonstrated at 1550 nm previously. 4 However, this approach has not, to our knowledge, been used before in visible or near infrared wavelengths. Recently, it has become possible to obtain fiber optic circulators for shorter wavelengths, with specifications comparable to those for free-space isolators. By using a fiber optic circulator, we eliminate most of the free-space components involved in a typical injection locking setup, and hence reduce the alignment sensitivity. The only free-...

A compact frequency-doubled diode-pumped Nd:YAG master-oscillator power-amplifier laser system with programmable microsecond pulse length has been developed. Analog pulse shaping of the output from a single-frequency continuous-wave Nd:YAG oscillator, and subsequent amplification, allowed the generation of rectangular pulses with pulse lengths on the order of the Nd:YAG fluorescence lifetime. Temporally flat-top pulses of 1064 nm light with 520 mJ pulse energy, 2.6 kW peak power, and 200 μs duration, with linewidth below 10 kHz, were obtained at a repetition rate of 2 Hz. Second harmonic generation in a LBO crystal yielded pulses of 262 mJ and 1.3 kW peak power at 532 nm. The peak power can be maintained within 2.9% over the duration of the laser pulse, and long-term intensity stability of 1.1% was observed. The spatially flat-top beam at 1064 nm used in the amplifier is converted to a Gaussian beam at 532 nm with beam quality factor M2 = 1.41(14) during the second harmonic generation. This system has potential as a pump source for Ti:sapphire, dye, or optical parametric amplifiers to generate tunable high-power single-frequency radiation for applications in precision measurements and laser slowing.