The new imager captures amplitude and phase information without digital processing

Researchers at the University of California, Los Angeles (UCLA) have achieved a significant breakthrough in optical imaging technology. A new all-optical complex field imager has been developed, capable of capturing the amplitude and phase information of optical fields without the need for digital processing.

This innovation promises to revolutionize various fields, including biomedical imaging, security, sensing and material science. The work was published in the journal Light: Science & Applications.

A paradigm shift in imaging

Traditional optical imaging technologies rely on intensity-based sensors that can only capture the amplitude of light, leaving out the crucial phase information. Phase information provides insight into structural properties such as absorption and refractive index distributions, which are essential for detailed sample analysis.

Current methods to capture phase information involve complex interferometric or holographic systems supplemented by iterative phase retrieval algorithms, resulting in increased hardware complexity and computational demand.

A team at UCLA, led by Professor Aydogan Ozcan, has developed a new complex field imager that overcomes these limitations. This innovative device uses a series of diffraction surfaces optimized for deep learning to modulate complex input fields. These surfaces create two independent imaging channels that transform the amplitude and phase of the input fields into intensity distributions in the sensor plane. This approach eliminates the need for any digital reconstruction algorithm, significantly simplifying the imaging process.

The new complex field image consists of spatially generated diffractive surfaces arranged to perform amplitude-to-amplitude and phase-to-intensity transformations. These transformations allow the device to directly measure the amplitude and phase profiles of complex input fields. The imager’s compact optical design spans approximately 100 wavelengths on axis, making it highly integrable into existing optical systems.

The researchers validated their designs through 3D-printed prototypes operating in the terahertz spectrum. The experimental results showed a high degree of accuracy, with the output amplitude and phase channel images closely matching the numerical simulations. This proof-of-concept demonstration highlights the potential of complex field imaging for real-world applications.

Applications and future perspectives

This breakthrough in complex field imaging technology opens up a wide range of applications. In the biomedical field, the imager can be used for real-time, non-invasive imaging of tissues and cells, providing critical insights during medical procedures. Its compact and efficient design makes it suitable for integration into endoscopy equipment and miniature microscopes, potentially advancing point-of-care diagnostics and intraoperative imaging.

In environmental monitoring, the imager can facilitate the development of portable lab-on-a-chip sensors for rapid detection of microorganisms and contaminants. Its portability and ease of use make it an ideal tool for on-site quantitative analysis, simplifying the environmental assessment process.

Complex field imaging also holds promise for industrial applications, where it can be used for rapid inspection of materials. Its ability to capture detailed structural information without the need for large hardware or extensive computational resources makes it a valuable asset in quality control and material analysis.

The development of the all-optical complex field imager represents a significant advance in the field of optical imaging. By enabling the direct capture of amplitude and phase information without digital processing, this technology simplifies the imaging process and expands the field of possible applications. As the research team continues to refine and expand their plans, the impact of this innovation is expected to grow, providing new opportunities for scientific research and practical applications in various fields.