We experimentally observe coherent generation of a near-infrared optical field through a three-wave mixing phenomenon in an atomic energy level scheme of 85 Rb atoms. This nonlinear generation process in a centro-symmetric thermally broadened atomic system is made possible through a novel interaction between induced electric and magnetic dipoles. The two-photon and three-photon coherence present in our scheme eliminates excited state decoherence. Thus, our scheme represents a minimal optical decoherence scheme which could be used to transfer quantum states between microwave-to-optical frequency regimes with near-unit fidelity. Nonlinear frequency conversion from microwave-to-optical frequencies has garnered a lot of attention in the past decade [1-3]. This is due to the ease of transport and detection of giga-hertz signals through optical channels and the essentially noise-free nature of the frequency conversion process. The latter attribute has been central to proposing high-fidelity classical and quantum conversion of signals between microwave and optical frequencies [4,5]. A range of devices has been proposed to demonstrate this frequency conversion phenomenon. Starting from the commonly used electro-optic-modulator, several authors have investigated carefully engineered whispering-gallery-mode resonators [6,7], micro-and nano-sized hybrid electro-opto-mechanical devices operating at a few kelvin [8,9], rare-earth doped crystals [10] and gaseous atomic systems with induced coherence [11] as viable architectures for effecting nonlinear frequency generation and signal transfer. In atomic systems, there have been several theoretical proposals [12-15], but very few experimental demonstrations [16]. These studies highlight various aspects of the nonlinear generation phenomenon such as efficiency, bi-directionality, and non-reciprocity. A four-wave mixing phenomenon has been a widely utilized nonlinear frequency generation process in atomic systems [17,18]. Beginning with lasing without inversion [19], experiments showing new frequency generation have been performed, which combine atomic coherence effects with a four-wave-mixing process [20-23]. In this Letter, we demonstrate a novel three-wave mixing process in a room temperature gaseous atomic vapor of 85 Rb atoms, which utilizes induced atomic coherence to generate a near-infrared optical field. This three-wave mixing process combines an electric dipole and a magnetic-dipole transition in optical and microwave frequency domains, respectively, leading to the generation of a new infrared frequency. A unique feature of our system is that despite thermal motion of our atomic ensemble at room temperature and despite resonant nonlinear interaction, the generation process is coherent. It is not affected by the Doppler width or by the decay processes from the excited states. This is due to the fulfillment of both two-photon and three-photon resonance conditions for our system by all the three fields. During the generation process of the probe field, the probe and the coupling satisfy a two-photon resonance that shelves the atoms in a dark state due to the electromagnetically induced transparency effect [24], making the process immune to noise effects due to spontaneous decay from excited states. As is well known, the two-photon resonance condition is Doppler free. This Doppler-free condition remains valid, even during the fulfillment of the three-photon resonance condition between the coupling, microwave, and the generated probe fields due to the smallness of the Doppler width for microwaves. Thus, due to a nonlinear interaction between induced electric and magnetic dipoles and due to the formation of atomic ground state coherence, we have demonstrated for the first time, to the best of our knowledge, the lowest-order coherent nonlinear frequency conversion process from an atomic ensemble. The bandwidth for coherent conversion from microwave-to-optical frequencies with this scheme is shown to be about 825 kHz. The efficiency of our conversion process is about 2.6 × 10 −4 %. The efficiency is mainly dictated by the weakness of a magnetic-dipole interaction induced by the microwave field. Nevertheless, the fidelity that could be achieved by our scheme for signal transfer will be very high due to the absence of major sources of decoherence in our conversion Letter Vol. 44, No.