Comment on 'Tunable terahertz-mirror and multi-channel terahertz-filter based on one-dimensional photonic crystals containing semiconductors' [J. Appl. Phys. 110, 073111 (2011)]

摘要

The authors present in their paper two different methods in order to make the reflection bandwidth of THz mirrors tunable and to manipulate the operation frequency of THz filters along with their bandwidth. The first method employs thermal tunability based on varying the intrinsic carrier concentration of the semiconductor, while the second makes use of "changing the thickness of the component materials in the one-dimensional photonic crystals". The authors explain the second method by breaking the periodicity and introducing defect layers into the one-dimensional photonic crystals (1D PhCs) and changing (tuning), thereby, the distance between the semiconductor/dielectric layers. They claim that this method, being "largely" ignored, is considered in their paper (with no further reference that is directly related to the topic). They further claim that they have designed a tunable THz mirror and a filter that is based on the above-mentioned working principle.