Product Details

The ZYGO 7702 is a discontinued air-cooled two-frequency He-Ne heterodyne laser head of ZMI series, designed to match ZMI 240X and 4X04 series interferometer measurement boards for high-precision displacement metrology in semiconductor equipment, precision positioning stages and optical measurement platforms. It outputs 632.8nm laser with two orthogonal linear polarization frequencies, fixed frequency difference of 20MHz ±1600Hz, providing stable reference beat signal for heterodyne interferometer decoding.

This laser head has two standard beam configurations, 3mm and 6mm beam diameter. The 6mm version supports maximum optical path distance up to 25 meters, suitable for long-stroke motion systems; the 3mm version is for short-stroke optical layout within 2 meters. The optical output power ranges from 400µW to 1mW, with typical frequency stability less than 0.1ppm per hour. It integrates built-in 30dB optical isolator to protect laser cavity from back reflection of interferometer optics, effectively avoiding frequency drift and lock loss. The power supply is ±15VDC and +5VDC, it takes about 25 minutes to reach full wavelength stability after power on. Multiple 7702 laser heads can be deployed in one system to supply optical signals for multi-axis measurement boards.

It is equipped with BNC RF beat output port, interlock and temperature monitoring interface. The front panel has power and laser status LED indicators for routine inspection and fault diagnosis. The shell adopts vibration damping structure and EMC shielding design, which suppresses electromagnetic interference from servo drivers and linear motors in cleanroom environments. Users need to select the correct beam diameter version and match corresponding interferometer, retroreflector and measurement board. Beam accessories of 3mm and 6mm are not interchangeable. This legacy ZYGO 7702 laser head is mainly supplied as spare replacement parts for existing ZMI metrology systems. Users need to verify optical power, frequency difference and beam specification before replacement. A conformal coated version is optional for high humidity and dusty industrial sites. This laser head is widely used in legacy laser interferometer system upgrade, wafer stage positioning and nanometer closed-loop motion feedback projects.

This two-frequency He-Ne laser head adopts standalone compact housing structure. It requires ±15VDC and +5VDC power supply. LED indicators display power and laser lock status for convenient on-site inspection. The optimal operating temperature range is 15°C to 30°C, storage temperature ranges from -40°C to +85°C, relative humidity 5% to 50% non-condensing. It complies with industrial shock, vibration and EMC standards and has CE certifications. It supports optical path calibration backup for fast recovery after hardware replacement.

This ZYGO 7702 laser head is widely applied in high-precision laser interferometer measurement systems. It provides stable two-frequency laser source for ZMI 240X and 4X04 series measurement boards. As a reliable spare part for ZYGO legacy metrology systems, the ZYGO 7702 retains original heterodyne frequency characteristics and optical compatibility, helping customers reduce maintenance cost of legacy ultra-precision measurement equipment.