Patent attributes
An electromagnetic wave generator encompasses a first pump beam emitter (2) configured to emit a first pump beam (hv1) having a wavelength larger than one micrometer; a second pump beam emitter (25) configured to emit a wavelength-tunable second pump beam (hv2) having a wavelength larger than one micrometer, the wavelength of which is different from the wavelength of the first pump beam (hv1); a nonlinear optical crystal (19) configured to generate an electromagnetic wave (hv3) of a difference frequency between the first pump beam (hv1) and second pump beam (hv2); and an optical system (M1, M2, 18) configured to irradiate the first pump beam (hv1) and second pump beam (hv2) to the nonlinear optical crystal (19), by adjusting an external intersection angle between the first pump beam (hv1) and second pump beam (hv2) within 0.5° at the difference frequency of 1 THz. Here, a frequency-tunable terahertz electromagnetic wave (hv3) is generated in the nonlinear optical crystal (19), by changing the frequency of the second pump beam (hv2), being liked with the change of the external intersection angle.
