Background introduction>>Introduction to the principle of terahertz near-field scanning imaging system

Terahertz waves have a wide range of applications in material detection and non-destructive testing due to their low photon energy, non-destructive and non ionizing properties More noteworthy is terahertz imaging, especially in biomedical imaging, which has attracted widespread attention. Terahertz imaging becomes a good choice when visible light cannot penetrate or X-ray contrast cannot meet the requirements. However, traditional far-field terahertz imaging systems are limited by diffraction limits, with a minimum resolution of only λ/2, corresponding to a minimum resolution of 0.15 mm for 1 THz. The millimeter level imaging resolution to some extent restricts the application of terahertz imaging technology. Therefore, the development of near-field detection and microscopy techniques is particularly important for achieving higher resolution. In order to break the diffraction limit and improve spatial resolution, Hunsche et al. developed a terahertz near-field imaging system, which increased the resolution of terahertz point by point imaging to the sub wavelength level. This work has elevated the performance of terahertz near-field imaging technology to a new level, opening up new avenues for the study of terahertz imaging.

Terahertz near-field detectionThe application areas and their advantages

——ExtremehighSpatial imagingbranchDistinguishRate and carry THzlightSpectrumThe unique characteristics of

Terahertz research	Thin film detection	Chip packaging measurement	Testing and screening
applicationfield： Metamaterials and plasmas Passive components • Radiation source • Antennas and waveguides • Sensor surface • Graphene	applicationfield： • Solar cells • Monitor • Flexible electronic devices • Semiconductors • Graphene • Transparent conductor	applicationfield： Time resolved reflectance measurement • Fault isolation • Packaging inspection 3D integration • Through Silicon Via Technology (TSV)	applicationfield： Laser plastic welding inspection • Polymer fiber optical fiber • Insufficient chip filling detection • Organic layer screening
Advantages of Tera Cube: • Near field greed for money Expansion of Terahertz Time Domain Spectrometer System for Accounting • High sensitivity • Low noise Polarization sensitivity • Broadband capability	Tera-Cubeexcellentspot： Thin film resistance imaging • Non contact measurement • Resolution in micrometer size • Large area scanning •High speed scanning imaging	Tera-Cubeexcellentspot： Market leading TDR solutions • Sub picosecond rise time • Non contact • Non destructive testing	Tera-Cubeexcellentspot： Non contact non-destructive testing • Quick detection • Screening of visible/infrared opaque plastics • Detection of micro scale structures

Product Introduction

The THz Cube terahertz near-field scanning imaging system launched by Yichi Optoelectronics breaks through the wavelength resolution limit and can increase the spatial imaging resolution to 3um. THz Cube is an automated terahertz near-field scanning system. The standard near-field scanning system launched by Yichi Optoelectronics can also be driven by the customer's own femtosecond light source. The requirements for the femtosecond light source are as follows:

Center wavelength: 770 nm ... 820 nm
Repetition frequency: 10 MHz ... 1 GHz
Average power: 60 mW ... 1.5 W
Pulse width:< 150 fs

Tera-Cube

Principle of Terahertz Near Field Scanning

Time domain spectrum&spectral data

Product Features

——High speed continuous scanning and data acquisition;

——Optical morphology detection ensures that the distance between the probe and the sample surface remains consistent during lateral scanning of the sample;

——High dynamic range phase-locked detection

——Linear polarization switchable terahertz transmitter capable of independent polarization state measurement

——Integrated CCD camera module to control probe head and sample position

——The control software can automatically control and adjust the distance between the sample and probe, and perform data collection and analysis

Sample testing

Example plots of the THz near-field distribution measured at a metamaterial surface for sensing applicationswhich is locally loaded with sample material. Left: Peak excitation state, right: 2 ps after excitation.