Generating millimeter and terahertz waves

Terahertz technologies: present and future

“…For the application to industrial instrumentation, use of 1550-nm laser wavelength is essential, since matured and cost-effective telecom-based components can be used including low-loss and low-dispersion optical fiber cables. Among 1550-nm photodiodes, uni-traveling-carrier (UTC) photodiodes and their modifications have exhibited the highest output power; >500 μW at 350 GHz, >100 μW at 350∼450 GHz, >10 μW at 1 THz [9,10]. More than one order of increase in the output power at >500 GHz is desirable for practical applications.…”

“…More than one order of increase in the output power at >500 GHz is desirable for practical applications. Figure 4 shows the structure of modified UTC photodiodes which optimize a tradeoff between the bandwidth and the responsivity [9]. One of the remaining practical issues in the high-power UTC and UTC-like photodiodes is thermal management.…”

Comparison of Monolithic Optical Frequency Comb Generators Based on Passively Mode-Locked Lasers for Continuous Wave mm-Wave and Sub-THz Generation

“…The first one aims to push the frequency limits of electronic devices to cover the sub-THz and THz regions [11], while the second one is based on the downconversion from the optical domain [12]. Several schemes and technologies have been proposed and developed in the last years following both trends, but in terms of potential integration, compactness, performance and cost-effectiveness, which are the requirements for the next generation of THz technology; the main candidates nowadays are Resonant Tunneling Diodes (RTDs) for the electronic approach [13], and optical heterodyning using two optical frequencies for the photonic technology [14].…”

Effective Generation of Milliwatt-Level Sub-Terahertz Wave for Nonlinear Response Measurement of Two-Dimensional Material by Optical Heterodyne Technique

“…Sub-terahertz (sub-THz) and/or terahertz (THz) wave, usually defined in the range of 0.1-10 THz, has been extensively researched owing to its importance for high-frequency wireless communications, radar systems, high resolution imaging applications, and nonlinear measurement systems [1][2][3][4][5][6][7]. Especially for areas of measurement domain, the nonlinear characteristic of materials at sub-terahertz band is an influential perspective but was neglected for a long time.…”