[China Instruments Network Instrument Development] If the prototype based on quantum dot wavelength “filter” can be successfully developed, the size of the spectrometer used in space applications will be greatly reduced.
Currently, NASA and MIT are working on a related collaborative project and plan to launch the system for the first time on CubeSat.
Principal Investigator Mahmooda Sultana
miniaturization
As a detection device, the spectrometer is almost carried on all spacecraft to complete space missions. NASA hopes to use quantum dot technology to change the construction and integration of existing spectrometers while achieving significant cost reductions.
The project was co-sponsored by a research team led by NASA Goddard Space Flight Center Mahmooda Sultana and MIT chemistry professor Moungi Bawendi, funded by the NASA Innovation Center Fund to support high-risk technology research and development.
Professor Bawendi's research team took the lead in the research of quantum dot technology from the early 1990s and developed applications in photovoltaics, biology, and microfluidics. At the same time, quantum dot technology has also begun to have a major impact on the consumer electronics industry. Many TV manufacturers are embarking on new technologies to improve LCD display quality.
Prof Sultana said that this method can achieve the miniaturization and revolutionary development of space-based and other types of spectrometers, especially those applied to unmanned aerial vehicles and small satellites. In a report to NASA, she stated that "quantum dot technology can indeed simplify instrument integration."
Initially, it can work in the form of absorption spectra instead of the traditional combination of optical components. Traditional spectrometers use gratings, prisms, or interference filters to split the light into different wavelengths, and then detect the resulting spectrum, and the quantum dots themselves can effectively filter the light.
The absorption or emission of light by the quantum dots depends on their diameter size - the smaller the size, the smaller the wavelength of light absorbed by the quantum dots - so in principle, different size quantum dot arrays can achieve the effect of similar optical devices. . Although the development of integrated optics and optoelectronic devices has made conventional spectrometers smaller, they are still too large.
Sultana explained: “Using conventional spectrometers such as gratings or prisms, the increase in spectral resolution will cause the optical path of the spectrometer to become longer and the volume of the instrument will generally be larger. However, in quantum dot spectrometers, quantum dots can be The difference in shape can absorb light of different wavelengths like a filter and the instrument can become ultra-compact. In other words, quantum dots can replace the use of optical elements such as gratings, prisms, and interference filters in traditional spectrometers."
Tunable wavelength filter
In theory, quantum dot spectrometers can achieve high resolution based on an infinite number of differently sized quantum dots.
Sultana said: "This will result in a continuously adjustable, independent set of absorption filters where each pixel consists of quantum dots of a specific size, shape or composition. We can precisely control the absorption of each quantum dot. , or custom instruments, to observe different bands with high spectral resolution."
Currently, Sultana is developing a 20×20 quantum dot array that is sensitive to visible light for imaging sunlight and aurora. In principle, the technology can be extended to a wider range of wavelengths, from ultraviolet light to mid-infrared light, enabling potential applications in many space fields such as earth sciences, solar physics, and planetary sciences.
NASA reports that Prof. Sultana is developing a concept instrument for cube satellite applications and that MIT student Jason Yoo is working on a technology that synthesizes different precursor chemicals to create quantum dots and print them to the appropriate printers. Things. Sultana said: "We hope to eventually print quantum dots directly onto the detector pixels."
Although the technology is still in the early stages of development, NASA researchers also added that they will work hard to improve the technology as soon as possible. Sultana said that there will be several space science missions that will benefit from this technology.
(Original Title: NASA and MIT Dedicated to Quantum Dot Spectrometer Research)

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