A 245.3 nm deep ultraviolet optically pumped AlGaN based multiple-quantum-well laser operating at room temperature is described. Epitaxial growth was performed by metalorganic chemical vapor deposition on a c-plane bulk AlN substrate at a growth temperature of ∼ 1130 °C. The wafer was fabricated into cleaved bars with a cavity length of ∼1.45 mm and the lasing threshold was determined to be 297 kW/cm2 under pulsed 193 nm ArF excimer laser excitation. A further ∼20% reduction in threshold pumping power density was observed with six pairs of SiO2/HfO 2 distributed Bragg reflector deposited at the rear side of facets.