HgCdte APD Optimization for Lidar Detection Of greeNhouse gases

Project Information

HOLDON

Grant agreement ID: 776390

DOI

10.3030/776390

Project closed

EC signature date 30 October 2017

Start date 1 January 2018

End date 31 March 2022

Funded under

• INDUSTRIAL LEADERSHIP - Leadership in enabling and industrial technologies – Space

Total cost

€ 2 508 571,25

EU contribution

€ 2 508 571,25

Coordinated by

COMMISSARIAT A L ENERGIE ATOMIQUE ET AUX ENERGIES ALTERNATIVES
France

Periodic Reporting for period 3 - HOLDON (HgCdte APD Optimization for Lidar Detection Of greeNhouse gases)

Reporting period: 2020-07-01 to 2022-03-31

Summary of the context and overall objectives of the project

LIDAR remote sensing of the earth’s atmosphere is one of the main challenges in coping with the effects and causes of global warming caused by the emission of greenhouses gases. The present operating Lidar missions for atmospheric monitoring are all implanted on large satellite platforms due to the size of the telescope and high energy laser modules required to ensure a sufficient collection of light to extract the signal from the detector noise. The HOLDON project aims to develop a new and versatile detection chain which will improve the performance of the Lidars, and/or to reduce the Lidar payload to be integrated in future mini-satellites.
The performance increase is obtained by the optimization of the optical coupling, quantum efficiency and gain performance of HgCdTe avalanche photodiodes (APD) that will be hybridized to a specifically designed CMOS readout circuit (ROIC) providing two operation modes. The devices are expected to meet the most demanding specifications for Lidar applications, from ultraviolet to near-infrared wavelengths, in terms of sensitivity, dynamic range, and temporal resolution (high dynamic range down to single photon sensitivity). 7 European partners (CEA/LETI, DLR, AIRBUS, IDQ, LMD, ALTER and ABSISKEY) are working together to address three objectives:
- design and manufacture a cutting-edge photon noise limited LIDAR detection chain.
- demonstrate the improvement achieved with the detection chain for green-house gases detection (notably CO2, CH4).
- validate the adequacy between Lidar detection key performances and requirements for future space missions.
The measured performance of the detection modules showed that they globally met the performance of the KPIs. Tests within the test set-ups were partially carried out, and are in line with the expectations. This should represent a guarantee that the HOLDON detector should find use in future atmospheric Lidar mission. These characteristics are also expected to open a new horizon of applications in fields beyond the field of atmospheric Lidar.
Despite the promising results, all the partners could not test the detectors within their Lidar setups in the timeframe of the project since a duration extension was not granted.

Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far

The first technical step consisted in the full definition of the specifications of the HOLDON detection chain (expected performances of the hybrid detectors and the acquisition chain) by the technical Partners, based on different ground-based and space LIDAR scenarios. These specifications were slightly updated (completed) during the second period.

Based on these specifications, the following main developments were made for the hybrid detectors:
-A CTIA architecture was used for the ROIC, offering a large dynamic range and a dual-operation mode (continuous mode or on-chip-sampling mode). The ROIC was designed and a CMOS batch with 200mm wafers was processed. Electrical pre-tests in a probe station showed that the ROICs had nominal characteristics with high yield.
-Two technological batches of APDs based on epitaxy-grown HgCdTe wafers were realized, and allowed getting APD variants with a gain quite above 100 (at low temperature) and suitable for the demonstrators.
- Specific cold PCBs were designed and manufactured.
- Hybrid components (APDs+ROIC) were bonded to the cold PCB and integrated into the LN2 or cryocoolers cryostats to form the detection modules.
The results obtained from the characterization of the modules showed that the HOLDON objectives for the detector modules have globally met the performance of the KPIs when characterized within the laboratory equipment. In particular, the high sensitivity, down to single photon level, combined with an ultra-high dynamic range and low recorded persistence. This performance should represent a guarantee that the HOLDON detector will find use in future atmospheric Lidar missions. Unfortunately, all the partners could not test the detectors within their Lidar setups. These characteristics are also expected to open a new horizon of applications in fields beyond the field of atmospheric Lidar.
Laboratory test results of the detector were presented at the ICSO2022, IAC2022 conferences and at a workshop held in Paris by CNES the 20/10/2022.

Regarding the control and acquisition chain:
- 5 back-end electronics systems (each system comprising 3 boards) were fabricated and validated.
- The FPGA building blocks (for pre-processing, timing and fast data transfer to a custom user) were validated through system integration.

In parallel, for laboratory tests, a Lidar Echo Emulator (LEE) was designed and implemented. The equipment can emulate signals at NIR, VIS, and UV wavelengths, for short-pulsed or long echoes, and can be controlled through a dedicated user interface.
Most of the measured parameters were in line with the expectations.
It is foreseen to present HOLDON results at the infrared detection for space applications workshop to be held in June 2023 in Toulouse, co-organized by CNES and ESA.

In view of the laboratory and field measurement of atmospheric methane, a test plan has been prepared to evaluate the new HOLDON detection module within 1.64 µm IPDA systems.
The opto-mechanical integration for the detection chain was partially completed up to the integration of the detection module.

For CO2 DIAL, a 2-µm laser source has been developed and the key performances of the 2-µm laser source have been assessed especially for pulse energy (>40 mJ), spectral purity (99.986%) and frequency stability (<70 kHz at 10s). Then, an optical detection chain, which will integrate the HgCdTe APD, has been built and now ready for the Lidar integration.
Lidar system has been tested in coherent detection. CO2 measurements from DIAL and in situ sensor agreed within the error bars and coherent detection will be used to check direct detection performances. Measurements with the APD detection module could not be carried in the timeframe of the project.

The dissemination activities are well on-going, with public communications through the website (http://holdon-h2020.eu) social media, and conferences/publications/posters. HOLDON is still attracting new people. The progress of the technical program has been delayed with the outbreak of the covid-19 virus but has regained its momentum.

Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far)

The HOLDON LIDAR detection module has globally met all the KPI. The partial measurements carried out with the versatile Lidar detection chain (from near UV to mid-IR) reached the expectations.
From these promising results, we expect to foster scientific excellence in Europe by conserving a leading position in the physics and applications of HgCdTe APDs, and by enabling new scientific collaborations, new markets and applications using the HOLDON-type detector.
This will also pave the way to a commercial (European) offer for atmospheric and space LIDAR applications with similar needs, with a potential industrial exploitation by some interested companies.
In a context where the global warming is a major issue for the future decades, a breakthrough observation of the atmosphere with much more precise datas will help to better survey the environment and assess emissions above cities, industrial or geological sites, carbone capture or dispersion modelling.
The project website audience has not stopped to increase since its creation, which shows that more and more people (from and outside the EU) got interest into the project progress.

Pictures of the 200mm CMOS wafers showing the specific HOLDON readout circuits (ROIC)

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Layout of the HOLDON read-out circuit

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