0000000000374712
AUTHOR
Kristians Draguns
showing 9 related works from this author
Uz čukstošās galerijas modu mikrorezonatoru bāzes veidotu sensoru modelēšana
2019
Darbā tiek pētīti uz čukstošās galerijas modu mikrorezonatoru bāzes veidoti sensori. Tiek veiktas datorsimulācijas ar programmu COMSOL Multiphysics. Datorsimulācijās tiek modelēti dažāda izmēra temperatūras sensori, kas atsevišķos gadījumos tiek salīdzināts ar eksperimentu. Vēl tiek modelēts sensors bio-slāņa biezuma noteikšanai, kas aplīp ap mikrorezonatoru. Kā arī sensors vienas molekulas noteikšanai.
High-Sensitivity Whispering Gallery Mode Humidity Sensor Based on Glycerol Microdroplet Volumetric Expansion
2021
We demonstrate a highly sensitive whispering gallery mode (WGM) relative humidity (RH) sensor based on a glycerol microdroplet. WGMs were excited using a 760 nm tunable semiconductor laser. We used free space coupling, which is effective when using a liquid resonator. A detailed analysis of different parameters influencing the sensor’s characteristics (sensitivity, hysteresis, resolution, stability, and temperature) is presented. The sensitivity of the sensor is one of the highest reported (2.85 nm/% RH in the range 50–70% RH with the resolution 1 × 10−4% RH). This type of humidity sensor has several advantages, such as high sensitivity, extended lifetime, good repeatability, and low cost, …
Whispering gallery mode resonators covered by a ZnO nanolayer
2020
Abstract The exceptional ability of whispering gallery mode resonators (WGMRs) to confine light within makes them interesting for sensing applications. The small size and high values of quality (Q) factors of the WGMR can be combined with a broad range of supporting optical elements. The surface of the resonator can be coated to enhance the desired attributes. In this paper, the impact of the ZnO layer thickness on the Q-factor of the WGMR has been studied. WGMRs were fabricated on a tip of a standard telecom fiber melted with an oxyhydrogen flame. The surface of the WGMR was coated with ZnO nanolayers of different thickness (5–100 nm) by atomic layer deposition (ALD). The Q-factor of as-pr…
Scattering loss analysis in PMMA WGM micro resonator from surface irregularities
2021
The following work shows new ways to analyze PMMA WGM micro resonators, that have irregularities, which acts as scattering centers. The scattering analyses could be used for integration into sensor systems and corrections of existing experiments.
ČUKSTOŠĀS GALERIJAS MODU MIKROREZONATORU DISPERSIJAS OPTIMIZĒŠANA KERRA FREKVENČU ĶEMMES ĢENERĒŠANAI VIENA SOLITONA REŽĪMĀ
2021
Viens no galvenajiem čukstošās galerijas modu mikrorezonatoru pielietojumiem ir frekvenču ķemmes ģenerēšana, kur monohromatiska lāzera signāls tiek pārkonvertēts vairākās frekvencēs ar regulāru intervālu starp tām. Priekš pielietojuma telekomunikācijās pie ierosinošā lāzera viļņa garuma 1550 nm frekvenču intervālam starp modām vajag būt ap 100 GHz. Lai panāktu frekvenču ķemmes ģenerāciju pie šādiem nosacījumiem, ir nepieciešams optimizēt rezonatora ģeometriju, lai tā raksturīgā dispersija ir līdzsvarā ar Kerra nelinearitāti. Darba mērķis ir izveidot tādu rezonatora ģeometriju, lai pie ierosinošā lāzera viļņa garuma 1550 nm rezonators darbotos viena solitona režīmā. Darbā tika atrasts, ka op…
Quality Factor Measurements for PMMA WGM Microsphere Resonators Using Fixed Wavelength Laser and Temperature Changes
2019
The whispering gallery modes (WGM) resonators are based on spherical objects, which are made from optically transparent materials, and are capable of maintaining circulating optical waves, inside the sphere, using total internal reflection. If there is a monochromatic light source which supplies the sphere with a constant intensity, the wave moving along the perimeter of sphere starts to constructively interfere. In this case the resonance happens, which is called whispering gallery mode (WGM). The current work explores the possibility of using temperature changes to measure polymethyl methacrylate (PMMA) WGM microsphere resonator quality factor (Q) and thermal expansion parameters. Differe…
Whispering Gallery Mode Resonator Temperature Compensation and Refractive Index Sensing in Glucose Droplets.
2021
Among the different types of photonic sensor devices, optical whispering gallery mode resonators (WGMRs) have attracted interest due to their high level of sensitivity, small size, and ability to perform real-time temperature measurements. Here we demonstrate the applicability of temperature measurements using WGMR in both air and liquid environments. We also show that WGMR allowed measurements of the refractive index variations in an evaporating glucose–water solution droplet. The thermal tuning of WGMR can be reduced by coating WGMRs with a thin layer of polymethyl methacrylate (PMMA). Dip-coating the silica microsphere multiple times significantly reduced the resonance shift, partially c…
Computer modelling of WGM microresonators with a zinc oxide nanolayer using COMSOL multiphysics software
2021
Whispering gallery mode resonators (WGMRs) are small axial symmetrical structures from transparent material, that can exceptionally well confine light within, thus making them ideal for studying light-matter interactions and using them as sensors. Various WGMR designs can be simulated using COMSOL Multiphysics. Sometimes an extra layer is coated on the surface of the resonator for achieving desirable effects. The extra layer changes quality factor of the resonator and ads extra modes for some frequencies. Different methods and studies are used for the exploration of this topic such as changing the thickness of the coating and using random functions to describe the roughness of the surface, …
Mode family analysis for PMMA WGM micro resonators using spot intensity changes
2021
The whispering gallery modes (WGM) micro resonators are based on elliptical objects, which can be made from optically transparent materials, The geometry of the object enables optical wave circulating inside the ellipse using total internal reflection. If there is a monochromatic light source with constant intensity to the ellipse, constructive interference may be observed. Poly methyl methacrylate acrylic (PMMA) WGM micro resonators are commercially available with typical optical quality factor of 103-104. These could limit problems with WGM micro resonator expensive manufacturing. Thanks to advances in high resolution image processing, read-outs using spectroscopy (single photo detector) …