Imaging weakly scattering phase objects, like cells, has captivated the attention of researchers in diverse fields, particularly the biomedical sciences, for numerous decades. To enhance image contrast, a prevalent method involves employing chemical stains or fluorescent tags. However, this approach necessitates intricate sample preparation procedures that may introduce toxicity or damage to the samples themselves. Addressing this challenge, quantitative phase imaging (QPI) has emerged as an influential label-free technique, offering non-invasive and high-resolution imaging of transparent specimens without the need for external tags or reagents.
Throughout various scientific disciplines, the quest to visualize delicate structures such as cells has always demanded innovative approaches. Biomedical scientists, in particular, have long sought methods to overcome the inherent difficulties posed by weakly scattering phase objects. Traditional techniques relying on chemical stains or fluorescent tags have undeniably played a vital role in enhancing visibility. Nevertheless, these methods often entail complex sample preparation steps, which not only consume precious time but can also inflict harm upon the very samples under scrutiny.
Enter quantitative phase imaging (QPI), a groundbreaking solution that has revolutionized the field through its label-free capabilities. By sidestepping the reliance on external agents, QPI offers a non-invasive means to observe transparent specimens with exceptional detail and resolution. Gone are the days when scientists had to resort to potentially toxic or destructive staining procedures; QPI grants them the ability to peer into the microscopic realm unencumbered.
The underlying principle of QPI lies in its ability to directly measure the optical path length variations encountered by light passing through the specimen. This innovative technique provides invaluable information about the refractive index distribution and thickness of the sample, enabling researchers to visualize and analyze subtle structural details with remarkable precision. Furthermore, QPI’s label-free nature preserves the integrity of the specimen, making it ideal for dynamic studies and long-term observations.
The advantages offered by QPI extend beyond its non-invasiveness. The absence of sample preparation steps simplifies experimental procedures, saving valuable time and resources. Researchers can now bypass the labor-intensive staining protocols that were once deemed necessary for visualizing weakly scattering phase objects. Moreover, the elimination of external agents eliminates the risk of introducing artifacts or altering the natural behavior of the specimens, allowing for more accurate and reliable observations.
The versatility of QPI is evident in its application across multiple disciplines. In the field of cell biology, for instance, QPI has become an invaluable tool for investigating dynamic cellular processes, such as cell division and migration, in real-time and over extended periods. Biomedical researchers can now delve into the intricate world of cells without perturbing their natural state, opening up new avenues for understanding fundamental biological phenomena and advancing medical research.
As technology continues to evolve, quantitative phase imaging stands at the forefront of innovation in the realm of imaging weakly scattering phase objects. Its label-free nature, high-resolution capabilities, and non-invasiveness have rendered it a game-changer in various scientific domains, particularly in biomedicine. By liberating researchers from the constraints of traditional staining methods, QPI empowers them to explore the hidden intricacies of transparent specimens with unprecedented clarity, bringing us one step closer to unraveling the mysteries of life at the microscopic level.
