Microfluidic Optical Devices

Microfluidic optical devices are classified into two groups of devices (1) devices using microscale on-chip optical methods/components for biochemical sensing or for manipulation of fluids or particles in Lab-on-a-Chip devices and (2) devices using microfluidics to manipulate light at the microscale. 

Microfluidic optical devices (MODs) represent an emerging technology that combines today s microfluidics technology with optics. Devices based on optofluidics -manipulating fluids and light at the microscale - are... 

Instead of fluorescence, absorbance can be used if the limits of detection are not too low and as long as the microchannels are transparent in the radiation region being exploited. Microfluidic CE devices have been fabricated from calcium fluoride (CaF2) to allow optical detection in the ultraviolet, visible and infrared spectral regions . Fast chiral CE separations have been carried out with UV detection . 

Aluminum possesses good electrical and thermal conductivity as well as its durability and availability makes it a preferable material for various microelectronics and MEMS applications. EMM of patterned A1 and Al-based alloys can be utilized in a wide range of applications, which includes energy storage devices microanalytical systems and microfluidic, optical, and microelectronic devices. EMM is economical and scalable to large geometric areas platform for microstructuring of A1 substrates. 

The droplet detection methods described in this entry include fluorescence, surface-enhanced Raman scattering (SERS), electrochemistry, capacitive, and mass spectrometry. The integration of different detection approaches into the microfluidic droplet device typically involves MEMS and optics technologies. Several methods have been employed to address the integration of detection components with the droplet operation unit however, the task of maintaining overall system functionality remains a challenge. As a result, most of these methods are significantly sophisticated. Trends and issues associated with each detection method are presented. 

The change of the carrier concentration would result in the change of refractive index due to plasma dispersion effect. If one of the SiGe optical branches was forward bias and another optical branch was reverse bias, the refractive index of the first optical branch would increase, while the refractive index of the second optical branch would decrease, leading to the optical switching to the first optical branch. The complex processes involved in constructing the device rendered it unable to be incorporated into microfluidic-related devices. 

The concept behind optical devices which incorporate liquids as a fundamental part of the optical structure can be traced at least as far back as the eighteenth century where rotating pools of mercury were proposed as a simple technique to create smooth spherical mirrors for use in reflecting telescopes. Modem microfluidics has enabled the development of a present-day equivalent of such devices, the development of which we now refer to as optofluidics. As will be described below, the capabilities in terms of fluidic control, mixing, miniaturization, and optical property tuning afforded by micro-, nano-, and electro-fluidics combined with soft lithography-based fabrication provide an ideal platform upon which to build such devices. 

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