Capturing blur-free images of fast movements has always been a challenge in the field of photography. Whether it’s falling water droplets or molecular interactions, the need for ultrafast cameras that can acquire millions of images per second has been a hindrance due to their high cost. However, a group of researchers has recently introduced a groundbreaking camera that could revolutionize high-speed imaging. In a paper titled “Diffraction-gated real-time ultrahigh-speed mapping photography,” published in Optica, the researchers unveil their new camera, which uses a completely new method to achieve high-speed imaging at a fraction of the cost of existing ultrafast cameras.
The team, led by Jinyang Liang from the Institut national de la recherche scientifique (INRS) in Canada, has developed a diffraction-gated real-time ultrahigh-speed mapping (DRUM) camera. This camera offers comparable imaging speed and spatial resolution to commercial high-speed cameras but utilizes off-the-shelf components that are significantly more affordable. According to Liang, the cost of their camera would likely be less than a tenth of today’s ultrafast cameras, which can start at close to $100,000.
Unleashing the Power of Time-Gating
Time-gating, a technique used to control when light hits the camera’s sensor, is a key factor in achieving high-speed imaging. Traditional cameras use a simple shutter as a gate that opens and closes once. However, the researchers have taken a different approach by developing a new time-gating method called time-varying optical diffraction. By leveraging the space-time duality of light, Liang and his team discovered that rapidly changing the tilt angle of the periodic facets on a diffraction grating could effectively gate out frames at different time points, enabling the capture of an ultrafast movie.
Implementing this innovative time-gating technique required the utilization of digital micromirror devices (DMDs). These are commonly found in projectors but have been utilized in an unconventional way to accomplish the swept diffraction gate in the DRUM camera. The advantage of using DMDs is their cost-efficiency and stability. These mass-produced components require no mechanical movement to produce the diffraction gate, making them ideal for creating an affordable and reliable high-speed camera.
Featuring a sequence depth of seven frames, the DRUM camera captures seven frames in each short movie. Researchers incorporated the camera into various experiments to showcase its capabilities. They successfully recorded laser interactions with distilled water, demonstrating the camera’s ability to capture the evolution of a plasma channel and the development of a bubble in response to a pulsed laser. The measured bubble radii aligned with predictions made by cavitation theory. Additionally, the camera was used to image the bubble dynamics of a carbonated drink and capture transient interactions between an ultrashort laser pulse and a single-layer onion cell sample.
Unlocking New Possibilities
DRUM photography holds immense potential for a wide range of applications. For instance, Liang believes it could contribute to advancements in biomedicine, automation-enabling technologies like lidar, nano-surgeries, and laser-based cleaning applications. The affordability and increased imaging speed of the DRUM camera could significantly impact these fields by allowing researchers and professionals to obtain more accurate data in real-time.
The Future of DRUM Photography
While the current version of the DRUM camera has already demonstrated remarkable capabilities, Liang and his team are committed to further enhancing its performance. They aim to increase the imaging speed and sequence depth, explore the possibility of capturing color information, and expand the range of applications that can benefit from this revolutionary technology. The researchers are also interested in delving into the world of lidar, a highly promising field where faster imaging could greatly enhance hazard sensing capabilities.
The development of the DRUM camera represents a significant breakthrough in the world of high-speed imaging. By utilizing a novel time-gating technique and digital micromirror devices, the researchers have created an ultrafast camera that is not only affordable but also comparable in performance to its expensive counterparts. The potential applications of DRUM photography extend beyond biomedicine and automation, offering researchers and professionals the opportunity to explore previously uncharted territory in various fields. With ongoing efforts to improve its performance, the DRUM camera is poised to revolutionize high-speed imaging and unlock new possibilities for scientific advancements.
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