1. Terahertz Technology Innovation Research Institute Terahertz Spectrum and Imaging Technology Cooperative Innovation Center Shanghai Key Lab of Modern Optical System University of Shanghai for Science and Technology 516 Jungong Road Shanghai 200093 China
2. Shanghai Engineering Research Center of Ultra‐precision Optical Manufacturing and Key Laboratory of Micro and Nano Photonic Structures (MOE) School of Information Science and Technology Fudan University Shanghai 200433 China
3. Department of Physics Shanghai University 99 Shangda Road Shanghai 200444 P. R. China
4. School of Physics University of Wollongong Wollongong New South Wales 2522 Australia
5. Department of Physics and International Laser Center Lomonosov Moscow State University Leninskie Gory 1 Moscow 19991 Russia
6. ILIT RAS‐Branch of the FSRC “Crystallography and Photonics”RAS Svyatoozerskaya 1 Shatura Moscow Region 140700 Russia