THz Generation and Detection by Fluorenone Based Organic Crystals

Direct study and control of material properties using terahertz (THz) frequency pulses is an emerging subject with strong potential for future applications. One aspect of the development of THz-based techniques is the search for new materials that can efficiently convert higher frequency light into the THz-frequency range and serve to detect and characterize weak THz radiation with high sensitivity. Here, the capabilities of a new class of THz generators and detectors based on diphenylfluorenone (DPFO) crystals are explored. We demonstrate that DPFO crystals have an extremely large electro-optical coefficients centered at around f ≈ 1.5 THz which makes them ideal for THz detection at this frequency. Excitation with intense femtosecond near-infrared pulses leads to emission of narrow-band (Δf/f ≈ 20%) THz radiation near 1.5 THz. This frequency range does not overlap significantly with water vapor absorption lines, which allows for practical applications under ambient conditions.