Nonlinear optical (NLO) single crystals
have become very useful
for second harmonic generation, fiber-optic communications, electro-optic
modulation techniques, terahertz (THz) wave generation and detection,
and other numerous applications. Researchers exploring crystals need
to identify appropriate NLO materials in order to achieve the aforementioned
objectives. In the present work, crystals of l-histidine
(LH), which is an amino acid, were successfully grown by a slow evaporation
technique over a period of 35 days. Powder X-ray diffraction (PXRD)
was used to determine the structural information and lattice parameters.
The functional groups and vibrational modes present in the compound
were confirmed by FT-Raman spectral analysis. The crystals were then
subjected to an etching study, which revealed that the crystal is
not significantly deformed by solvent action. Optical characteristics
were studied under UV–vis spectroscopy and photoluminescence
(PL) analyses. It has been found that the crystal has a broad transparency
between 250 and 900 nm, which makes it suitable for second harmonic
generation (SHG) of lasers in the blue region of the electromagnetic
spectrum (EM). The low frequency absorption spectra for LH single
crystals in the range of 0.8 to 2.5 THz were analyzed by terahertz
time-domain spectroscopy (THz-TDS). The THz spectra of LH show that
the THz wave is highly sensitive to the crystal, and the refractive
index was also evaluated at different frequencies. The stability to
temperature and thermal phase changes of LH were investigated using
thermogravimetric analysis (TGA) and differential thermal analysis
(DTA). The value of the laser-induced damage threshold was discovered
to be 4.65 times greater than the potassium dihydrogen phosphate (KDP)
value. The third-order nonlinear behavior of the LH single crystal
was investigated using a 10 ns pulsed Nd:YAG laser operating at wavelengths
of 1064 and 532 nm. The nonlinear optical parameter α for the
LH crystal was determined through Z-scan measurements.