Luminescent surfaces with tailored angular emission for compact dark-field imaging devices

Abstract

Dark-field microscopy is a standard imaging technique widely employed in biology that provides high image contrast for a broad range of unstained specimens 1. Unlike bright-field microscopy, it accentuates high spatial frequencies and can therefore be used to emphasize and resolve small features. However, the use of dark-field microscopy for reliable analysis of blood cells, bacteria, algae, and other marine organisms often requires specialized, bulky microscope systems, and expensive additional components, such as dark-field-compatible objectives or condensers 2,3. Here, we propose to simplify and downsize dark-field microscopy equipment by generating the high-angle illumination cone required for dark field microscopy directly within the sample substrate. We introduce a luminescent photonic substrate with a controlled angular emission profile and demonstrate its ability to generate high-contrast dark-field images of micrometre-sized living organisms using standard optical microscopy equipment. This new type of substrate forms the basis for miniaturized lab-on-chip dark-field imaging devices, compatible with simple and compact light microscopes.

Bandwidth limits of luminescent solar concentrators as detectors in free-space optical communication systems

“…However, étendue need not be conserved when Stokes shift is present, so the devices can simultaneously achieve high-concentration gain and a wide field-of-view, without violating the second law of thermodynamics 7 , 8 . Apart from photovoltaics, LSCs have attracted considerable interest for a diverse range of applications, including dark-field imaging 9 , microreactors 10 , greenhouse coatings 11 , and even dynamic systems (where the time of photon arrival is of essence), such as image recording and movement detection technologies 12 , 13 and free-space optical communications. In the latter case, LSCs were introduced as an efficient means to collect the diffuse light generated by modulated light-emitting diodes (LEDs) in visible light communication (VLC) systems 14 , a concept serving as the paradigm in this paper and which is depicted in Fig.…”

An optic to replace space and its application towards ultra-thin imaging systems

“…Therefore, a spaceplate is an optical element complementary to the lens. Nonlocal response engineering has been a fruitful research direction bearing applications, such as angular pass-filtering 39 , image processing [40][41][42][43] , and analog computing 36 . One previous work in nonlocal responses used a lens system similar to a 4f telescope to impart a k-dependent phase and magnitude response 36 .…”

Planar photonic chips with tailored angular transmission for high-contrast-imaging devices

“…On the other hand, a renewed interest in transmitted dark eld microscopy has arisen due to its advantage when used in combination with uorescence microscopy. Compared to uorescence emission from quantum dots (QDs) for the illumination source in luminescent-surfacebased dark eld imaging 14 , the scattered light originating from the high-intensity LED light can excite uorophores more e ciently than the uorescence-light from QDs. Also, the LED light source will not encounter the problem of photobleaching or blinking that is typical for QDs and other uorophores, then the proposed C-DFM and C-TIRM will be more stable.…”

“…The combination of ptychographic coherent diffractive imaging with sub-surface nanoaperture arrays was shown to yield an enhancement of both the reconstructed phase and amplitude 13 . A luminescent photonic substrate with a controlled angular uorescence emission pro le was used in a conventional microscopy to replace the bulk condenser for miniaturized lab-on-chip dark eld imaging devices 14,15 .…”