Iron doped Cd x Mn 1-x Te crystals, a new gain media for Mid-IR room temperature lasers W. Mallory a , V.V. Fedorov *a , S.B.Mirov a , U. Hömmerich b , W. Palosz c , S.B. Trivedi c a Department of Physics, University of Alabama at Birmingham, CH 310, 1530 3rd Avenue South, Birmingham, Alabama 35294, USA; b Department of Physics, Hampton University, Hampton, Virginia 23668 c Brimrose Corporation of America, 19 Loveton Circle, Baltimore, MD 21152-9202, USA ABSTRACT The objective of this study is to determine feasibility of ternary Fe:CdMnTe crystals for room temperature lasing in the mid-infrared spectral range. Fe:CdMnTe samples were grown with a modified Bridgman technique. At room temperature, Fe:CdMnTe features wide (2800-6000nm) absorption and emission (3700-6500nm) bands. The kinetics of the photoluminescence were measured over 14K-300K temperature range under 2920nm and 532nm excitation. The low temperature (14K) kinetic of luminescence under 2920nm excitation was a single exponential with a decay time of 75μs. The room temperature emission cross-section was estimated to be 2x10 -18 cm 2 . Keywords: Mid-IR solid-state lasers; Transition metals lasers 1. INTRODUCTION Transition metal doped chalcogenide wide-band semiconductors have attracted significant interest as promising gain media for room temperature mid-infrared (MIR) lasing. The main objective in the study of these crystals is identification of their spectroscopic characteristics and development of low loss gain materials capable to efficiently lase at room temperature over a broad MIR spectral range. The catalyst for these studies is the vast practical application of this type of lasers to a large variety of technological fields including: eye-safe laser radar, remote sensing of atmospheric constituents, trace gas analysis, environmental monitoring, industrial control, eye-safe medical laser sources for noninvasive medical diagnostics, optical communication, and numerous military applications such as target designation, obstacle avoidance and infrared countermeasures. In spite of the great potential of these gain materials only few of them exhibit a high enough quantum yield of fluorescence at room temperature suitable for room temperature lasing. Chromium doped chalcogenides such as: Cr:ZnS, Cr:ZnSe, Cr:CdTe, Cr:CdSe and Cr:CdMnTe have been extensively studied and came of age as materials of choice for effective room temperature lasing over 2.0-3.5μm spectral range. First room temperature lasing effects of iron doped ZnSe were recently documented over 3.9-5.0 μm spectral range [1]. Search for new laser materials capable of direct room temperature lasing over 4-6 μm spectral range is of great importance. Until now, there have been no reports of the optical or kinetics properties of iron doped cadmium manganese telluride. However, studies of optical and kinetic properties of chromium and cobalt doped cadmium manganese telluride showed that they are promising for lasing over 1750-3500nm and 3000-4250nm, respectively. [2]. The specific interest in Fe:Cd 0.55 Mn 0.45 Te as opposed to other types of similar crystals is based on unique properties of its crystal lattice. The iron ions are in tetrahedral symmetry, which is an advantage over cubic or octahedral symmetry in terms of smaller values of the crystal field. This results in smaller energy splitting of impurity ion in the lattice, which causes the emitted photons to carry less energy, and therefore shifts the emitted wavelength further into the MIR. Fe:Cd 0.55 Mn 0.45 Te has a smaller crystal field in comparison to ZnSe which also shifts the wavelengths further into the MIR. Also, the Te acts as a heavy ion host, of 127.6 a.m.u. nearly twice the mass of Se 78.96 a.m.u., which decreases the phonon cutoff with * vfedorov@phy.uab.edu ; phone (205)-934-5318 Solid State Lasers XVII: Technology and Devices edited by W. Andrew Clarkson, Norman Hodgson, Ramesh K. Shori Proc. of SPIE Vol. 6871, 68712T, (2008) · 0277-786X/08/$18 · doi: 10.1117/12.764236 Proc. of SPIE Vol. 6871 68712T-1 2008 SPIE Digital Library -- Subscriber Archive Copy