Lecture 38. New Technologies For Applications  Introduction  Holographic Optical Elements (HOEs)  Novel Doppler-Free  New  New Diagnostic Instruments  New Detectors and Receivers  New Filters and Fibers  Outlook Introduction  Lidar technology development is mainly driven by three factors: (1) Measurement needs (science and application driven), (2) New physical interaction and process findings, and (3) New technologies development.  Among these factors, new technology may be the most active factor as many new and optical detector technologies are becoming available. They are more powerful, stable, precise, and/or compact, enabling new or lidar applications.  Also with more powerful computers become available and cheaper, data acquisition (DAQ) and system control are in the revolution to replace traditional instruments with computer cards.  It is necessary to keep an eye on the new technologies, and always look forward to the next level development and improvement. Holographic Optical Elements (HOE)

Holographic Conical Scanning Telescope Holographic Optical Element (HOE)

Courtesy of Geary Schwemmer Lidar with HOE

Courtesy of Geary Schwemmer Angle multiplexed HOEs

Courtesy of Geary Schwemmer Application of HOE in Airborne Fe Doppler Lidar

Outgoing Return Laser Signal o Advanced Fe-Resonance/Rayleigh/Mie Doppler Lidar 35 Aircraft Viewport Window Holographic CW Dual Pulsed Alexandrite 744 nm Scanner f s fs Frequency 372 nm Ring-Laser Injection Acousto-Optic Doubler Seed Laser Frequency Shifter fs+ f (Oscillator + Amplifier) - fs f High-Resolution Frequency Cassegrain Trigger meter Reference & Spectrum Analyzer Telescope

Inquiry & Control Data Acquisition Record Pulse and Spectrum Control System Field Stop Signal PMT Collimating Interference Fabry-Perot Filter Etalon Chopper High-performance Instrumented Airborne Platform for Environmental Research (HIAPER)

Proposed Doppler Lidar Novel Doppler-Free Spectroscopy

 Saturation-fluorescence spectroscopy  Saturation-absorption spectroscopy  spectroscopy  Zeeman

0.90

0.85 Transmitted Laser Power without Pump Transmitted Laser Power with Pump 0.80

0.75

0.70

0.65 Transmitted Power (Arb. Unit) 0.60

0.55 0.40 0.45 0.50 0.55 0.60 PIEZO Scan Voltage (Arb. Unit) New Lasers for Lidar  Alexandrite ring laser, Nd:YAG family lasers  Femeto-second lasers  Diode lasers  Fiber lasers  … …

Fiber Diode Laser Amplifier

Diode Pump Laser New Diagnostic Instruments

 Wavelength Meter for cw and pulse lasers  Spectrum Analyzer for cw and pulse lasers  Laser Beam Profiler  Energy/Power Meters

 with new accuracy, precision, resolution, speed, etc. New Detectors, Filters, Receivers, and Fibers  Photo multiplier tube (PMT)  Avalanch photo diode (APD)  CCD

 Large optical mirrors  Computer cards for DAQ and data processing

 Etalons  Atomic and molecular filters

 Numerous new fibers Outlook for Lidar  Lidar remote sensing is an advanced technology that is not only replacing conventional sensors in science study, environmental research, and industry application, but also creating new methods with unique properties that could not be achieved before.  Lidar technology has been advanced dramatically in the past 20 years, owing to the new availability of lasers, detectors, creative people involved, and the demanding needs from various aspects.  Potential growing points at this stage include (1) Solid-state resonance fluorescence lidar for mobile deployment globally (2) Extend measurement range into thermosphere and lower mesosphere (3) Doppler, DIAL, HSRL, and Raman lidar for lower atmosphere research (4) Target lidar for novel applications  Always keep eyes open for new potentials: principles, phenomena, effects, and technologies to be applied in lidar remote sensing.