Capturing fast movements with clarity and precision has always been a challenge in the field of imaging. Conventional methods, such as high-speed cameras, often come at a high cost and can be complex to implement. However, a breakthrough in the field of ultrafast imaging has emerged with the introduction of a new camera that offers a much more affordable solution. Researchers from the Institut national de la recherche scientifique (INRS) in Canada, in collaboration with Concordia University and Meta Platforms Inc., have developed the diffraction-gated real-time ultrahigh-speed mapping (DRUM) camera. This innovation has the potential to revolutionize various applications, including drug delivery monitoring and high-speed lidar systems for autonomous driving.
In their paper titled “Diffraction-gated real-time ultrahigh-speed mapping photography,” the team demonstrates the capabilities of the DRUM camera, which can capture dynamic events at an incredible rate of 4.8 million frames per second. This level of imaging speed and spatial resolution is comparable to that of commercial high-speed cameras. However, what sets the DRUM camera apart is the utilization of off-the-shelf components, significantly reducing the cost to a fraction of traditional ultrafast cameras.
The potential applications of DRUM photography are immense. In addition to enabling advancements in biomedicine and automation technologies like lidar, faster imaging can enhance the accuracy of hazard sensing. Moreover, the versatility of DRUM photography allows it to be integrated seamlessly with CCD and CMOS cameras without compromising their other benefits, such as high sensitivity.
Traditionally, cameras use gates to control when light reaches the sensor. Gate operations, like the opening and closing of a shutter, determine the exposure time of an image. The researchers behind the DRUM camera developed a novel time-gating method called time-varying optical diffraction to overcome the limitations of existing ultrafast imaging techniques.
By exploiting the space-time duality of light, Jinyang Liang, one of the lead researchers, discovered a way to achieve time gating using light diffraction. By rapidly changing the tilt angle of periodic facets on a diffraction grating, the camera is capable of generating multiple replicas of incident light in different directions. This innovative approach allows for the gating out of frames at different time points, creating a collection of frames that can be compiled to form an ultrafast movie.
To turn this groundbreaking idea into a working camera, the multidisciplinary team combined their expertise in physical optics, ultrahigh-speed imaging, and MEMS design. They employed a digital micromirror device (DMD), a widely available optical component used in projectors, in an unconventional manner to accomplish the swept diffraction gate. The advantage of using DMDs is that they are mass-produced and do not require any mechanical movement, making the DRUM camera cost-efficient and stable.
The DRUM camera developed by the team has a sequence depth of seven frames, meaning it captures seven frames in each short movie. After characterizing the system’s spatial and temporal resolutions, the researchers conducted several experiments, including imaging laser interactions with distilled water and the dynamics of a carbonated drink bubble. These experiments successfully demonstrated the camera’s ability to capture complex and fast-paced phenomena.
The researchers are committed to further enhancing the performance of DRUM photography. They aim to increase the imaging speed and sequence depth while exploring the capture of color information. Additionally, the team plans to apply the DRUM system to a wider range of applications, such as nano-surgeries and laser-based cleaning.
The development of the DRUM camera presents a significant breakthrough in the field of ultrafast imaging. Its affordability and high-speed imaging capabilities open up possibilities for various industries, ranging from biomedicine to autonomous driving. With ongoing research and improvements, DRUM photography has the potential to revolutionize the way we capture and analyze fast movements, contributing to advancements in science, technology, and beyond.
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