Fabrication of 4.4 THz quantum cascade laser and its demonstration in high-resolution digital holographic imaging

Frequency regulation of Terahertz quantum cascade lasers by changing barrier thickness

“…where R 1 and R 2 are reflectivity of the cleaved facet and coated facet which are assumed as 0.32 and 1, respectively. a w has been experimentally measured in the range of 5 ∼ 7 cm −1 in our previous work and other reports [12,19,20], thus a maximum value of h i can be estimated as 0.50 and 0.28 per cascade period in pulsed mode at 15 K. Spectra collected using a Fourier transform spectrometer at several temperatures are shown in figures 4(a) and (b). The resolution of the spectra is 0.5 cm −1 .…”

THz coherent lensless imaging

“…According to them, the tested uncooled microbolometers are 40 times more sensitive than the pyroelectric camera Pyrocam III. As a consequence, the high detectivity of infrared microbolometers allows working with mW-level output sources such as QCLs or various FIRL lines [82,[110][111][112][113]. Their pixel pitch of 17-25 µm is ideal for off-line holography, as it allows large off-axis angles.…”

The quantum confined Stark effect in N-doped ZnO/ZnO/N-doped ZnO nanostructures for infrared and terahertz applications

“…Terahertz radiation (THz) refers to a broad electromagnetic spectrum range between microwaves and infrared waves (0.1 to 10 THz), also known as the terahertz gap. This spectral range provides a variety of possible applications including imaging, chemical sensing, biological sensing, high-speed telecommunications, security, optoelectronics, and medicine [1][2][3][4][5][6][7][8][9][10]. However, one of the major challenges in THz technology is the difficulty in finding suitable materials capable of providing energy efficient THz sources, because metals are typically not suitable due to the absorption losses at these frequencies [11].…”