[摘要]：Recent theoretical calculations predicted an order-of-magnitude increase in the efficiency of terahertz pulse generation by optical rectification in lithium niobate when 500 fs long pump pulses are used, rather than the commonly used similar to 100 fs pulses. Even by using longer than optimal pump pulses of 1.3 ps duration, 2.5x higher THz pulse energy (125 mu J) was measured with 2.5x higher pump-to-THz energy conversion efficiency (0.25%) than reported previously with shorter pulses. These results verify the advantage of longer pump pulses and support the expectation that mJ-level THz pulses will be available by cooling the crystal and using large pumped area. (C) 2012 Optical Society of America
