Applications

Nano-Spectrometers on a Chip
Hand-held Compact Chem/Bio Sensors
Interconnecting Elements for Photonic Lightwave Circuits (PLC)
Laser Mode Selectors and Beam Combiners

Our Digital Planar Holograms are as small as a few cubic millimeters and can be coupled directly with a fiber, a ridge waveguide, and/or a detector array, which results in a dramatic reduction in size and weight of a spectrometer, integrated on a chip.
We fabricated and successfully tested several visible band spectroscopes, shown in the graph below in coordinates Resolving Power versus Number of Channels N.

Series 1: 1000-channel spectroscopes with resolving power 10³ - 2.10³ (spectral resolution 10^-3 - 5.10^-4) and the output port pitch as small as 1 micrometer;
Series 2: 64-channel high-resolution spectroscopes with resolving power up to 10⁵ (spectral resolution ~10^-5);
Series 3: 64- and 128-channel spectroscopes with resolving power ~10⁴ (spectral resolution ~10^-4);
Series 4: 4-channel spectroscopes with resolving power 2.8.10² (spectral resolution ~3.6.10^-3).

For Series 1 spectroscopes the total length was 2.5 mm, while the hologram length was only 1.5mm. The hologram consisted of lines 90 nm wide and 10 nm deep, etched on the upper core surface of a planar light waveguide.

First industrial application should be a handheld system for express steel scrap sorting and field analysis. The spectrometers can be designed for absorption, emission, and Raman configurations. Their advantages will be most fully realized for spectrometry of compact areas and volumes, like in Raman spectroscopy, Laser Induced Breakdown Spectroscopy (LIBS), absorption spectroscopy in evanescent fields (bare fibers or planar waveguides, immersed into analytes).

Optical spectrometry allows for reliable and fast detection of chem/bio substances in air and water. A miniature size of our nano-spectrometers allows for constructing compact and inexpensive chem/bio sensors for creating a protective network around highly populated areas or high value assets. Each of the sensors will work autonomously with minimum maintenance and will transmit the data through a wireless data link to the central station. The network can function by polling all sensors periodically or by generating alarm from a sensor, which has detected something dangerous. Projected low cost of our spectrometers in mass production will make such kind of safety network real in the nearest future.
Miniature size of the sensors will allow them to be embedded into cell phones, in order to make this warning network mobile and reconfigurable. An artistic vision of such a device is depicted below.

igital Planar Holograms, developed by NOD, connect hundreds of points in a planar waveguide at desirable light wavelength. Since holograms are made from identical nano-features, manufacturing is simple and inexpensive. The DPH technology is ideal for interconnecting PLC components on-a-chip as it is shown in a diagram below. It is important that our holograms are several times smaller than traditional devices, for example Arrayed Waveguide Gratings (AWG) and are more robust than the AWG. The latter is associated with high DPH tolerance to local defects as the entire area of a hologram is involved in light processing and small local defects are not fatal.

NOD proprietary software supports the design of customized optical interconnects on any material planar waveguide.
Tell us what task you want accomplished and we will design and fabricate appropriate DPH components. Contact us to discuss how your interconnect problem can be solved with our Technology.

Semiconductor lasers provide generation of high power beams from very compact and efficient devices, however, the beam quality is not quite satisfactory for many applications, requiring high brightness. The main reason for high beam divergence in powerful wide aperture lasers is its multimode structure. Commonly used mode selectors are bulky and lossy and by these reasons were not accepted by the industry. Our innovative mode selector is based on the DPH technology and is implemented in a small planar chip. It can be butt-coupled to a wide aperture laser as shown in the picture or embedded into the laser planar as an additional integral component, providing single-mode generation from a wide area.
Proof-of-principle experiments were conducted with near-infrared wide emitting area laser diodes, butt-coupled to a planar waveguide chip with a core-embedded DPH mode selector (see the diagram below).

The DPH mode selector forces all zones in the wide area laser diode to generate the same mode. As a result, a multimode laser starts generate a single mode of much lower divergence and higher brightness, which can be focused into a tighter spot.
First results of practical implementation are shown in the following pictures. A multimode wide area laser diode originally had the slow axis divergence ~ 20 degrees and spectral width ~ 4 nm - upper graphs. After AR coating the output face and butt-coupling a DPH mode selector the laser beam divergence decreased more than 4 times, while the spectral width narrowed by an order of magnitude - lower graphs.

These results validate the concept and confirm that the approach is correct.
Alternatively, a DPH beam combiner can combine beams from all single-mode lasers, placed in the resonator, into a low-divergence single-mode beam.
We continue working on coupling optimization and on implementation of a monolithic structure with the laser diode and the DPH mode selector (or beam combiner) on a single wafer.