Introduction: Terahertz (THz) waves with frequencies in the range of 0.1 to 10 THz are electromagnetic radiation with growing applications in various fields of science and technology. Attractive features of this radiation have brought out many novel possibilities for medical diagnostics and treatments with considerable advantages compared to other conventional methods. Methods: In this paper, we present a review of more recent reports on practical applications of THz radiation for diagnostic, biosensing and clinical treatments. The review includes the diagnosis of breast, skin, mouth, cervical, lungs, small intestine, prostate, colon, and stomach cancers, the evaluation of biomolecules, the detection of genetic mutations, the determination of burn depth, the diagnosis of tooth decay, diabetes, and emotional-psychological states, the evaluation of corneal water to diagnose visual diseases, and wound healing monitoring. Further, it embraces the use of THz therapy in reducing the size of the tumor, treating skin cancer, and healing burn wounds, cardiovascular disease, corneal epithelium, angina, and THz heating. Results: This review has emphasized the capabilities of THz waves as a novel tool for future clinical diagnostics and treatments. Conclusion: The paper provides a comprehensive understanding of the feasible potential application of THz waves for clinical purposes and its advantages in comparison with other conventional tools.

ABSRTACTIn this paper, a new type of dynamic chemical etching is used to fabricate different fiber tips with different cone angles. It was done by controlling surface level of hydrofluoric acid relative to the fiber, with changing volume of the acid in the container using a syringe pump. Using this method the cone angle of the tip is effectively controlled and angles between 1 o and 30 o was obtained.

Recently, optical fiber tips have been used in many scientific applications requiring a special tip with predetermined cone angle. In this study, we have developed a new type of dynamic chemical etching for fabricating fiber tips which enables us to fabricate tips with predetermined cone angles. The fiber tips are fabricated by injecting or withdrawing hydrofluoric acid to the container in which the fiber is vertically inserted. By changing the flow rate of the acid injection or withdrawal, the height of fiber in contact with the acid can be controlled. This method produces cone angles from 3 to 33 degrees. Additionally, a model is proposed for this procedure which covers all the special cases and is in good agreement with the experimental results.H.

We propose terahertz wave generation using a parametric oscillator based on phase-matched and non-phase-matched degenerate four-wave mixing processes within a silicon nitride Fabry–Perot microcavity. The central frequency of the generated terahertz waves would be tunable over the frequency range of 3.6–5.73 THz by varying the wavelength of the pump wave. The best phase-matching condition is achieved at a frequency of 5 THz, and an optimum peak power of 329 W is obtained at a frequency of 4.29 THz.

We propose a structure of porous core photonic crystal fiber with a suspended and porous elliptical core that provides considerable properties for terahertz wave guidance. The propagation features of the structure are simulated and compared over the terahertz frequency region when TOPAS and silicon nitride are used as based materials. Our results reveal that the TOPAS based structure could enhance the birefringence up to 0.123 at the frequency of 1.4 THz, with a relatively comparable total loss of 0.2 cm−1. Moreover, it is confirmed that introducing silicon nitride as the base material to the proposed structure leads to a significant birefringence of 0.89 at the frequency of 0.6 THz, with a confinement loss of 10−4 cm−1 and effective material losses of 10−3 cm−1.