KRATKY, Jakub. Monitoring the activation of selected muscle groups of clients with spinal cord injuries. Prague: Charles University, Faculty of Physical Education and Sport, 2013. 82 pages. Supervisor Doc. PaedDr. Karel Jelen, CSc The aim of this thesis is to monitor the activation of selected muscle groups (musculus deltoideus pars anterior, musculus deltoideus pars posterior, musculus triceps brachii caput laterale and musculus trapezius pars descendus) during double poling ergometry. Nine subjects with different spinal cord lesions volunteered to participate in the study. The surface electromyography is used to detect the musculus activation. The monitoring of four muscle groups is devided into three phases. Firstly, all the participants double-poled for one minute at moderate intensity according to the Borg scale. Each participant underwent a 10-minute intervention to correct the posture. In the last phase the volunteers exercised again for one minute at moderate intensity. The aim of the intervention is to decrease muscle activation of musculus deltoideus pars anterior and musculus trapezius pars descendus (muscles with a tendency to hypertonia during wheelchair propulsion and activity of daily living) and to increase muscle activation of musculus deltoideus pars posterior and musculus triceps...

Entanglement is the hallmark of quantum mechanics. Quantum entanglement -- putting two or more identical particles into a non-factorable state -- has been leveraged for applications ranging from quantum computation and encryption to high-precision metrology. Entanglement is a practical engineering resource and a tool for sidestepping certain limitations of classical measurement and communication. Engineered nonlinear optical waveguides are an enabling technology for generating entangled photon pairs and manipulating the state of single photons. This dissertation reports on: i) frequency conversion of single photons from the mid-infrared to 843nm as a tool for incorporating quantum memories in quantum networks, ii) the design, fabrication, and test of a prototype broadband source of polarization and frequency entangled photons; and iii) a roadmap for further investigations of this source, including applications in quantum interferometry and high-precision optical metrology. The devices presented herein are quasi-phase-matched lithium niobate waveguides. Lithium niobate is a second-order nonlinear optical material and can mediate optical energy conversion to different wavelengths. This nonlinear effect is the basis of both quantum frequency conversion and entangled photon generation, and is enhanced by i) confining light in waveguides to increase conversion efficiency, and ii) quasi-phase matching, a technique for engineering the second-order nonlinear response by locally altering the direction of a material's polarization vector. Waveguides are formed by diffusing titanium into a lithium niobate wafer. Quasi-phase matching is achieved by electric field poling, with multiple stages of process development and optimization to fabricate the delicate structures necessary for broadband entangled photon generation. The results presented herein update and optimize past fabrication techniques, demonstrate novel optical devices, and propose future avenues for device development. Quantum frequency conversion from 1848nm to 843nm is demonstrated for the first time, with >75% single-photon conversion efficiency. A new electric field poling methodology is presented, combining elements from multiple historical techniques with a new fast-feedback control system. This poling technique is used to fabricate the first chirped-and-apodized Type-II quasi-phase-matched structures in titanium-diffused lithium niobate waveguides, culminating in a measured phasematching spectrum that is predominantly Gaussian (R^2 = 0.80), nearly eight times broader than the unchirped spectrum, and agrees well with simulations.

Made available in DSpace on 2014-06-11T19:25:31Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-02-17Bitstream added on 2014-06-13T19:12:21Z : No. of bitstreams: 1 escanhoelajunior_ca_me_rcla.pdf: 2205069 bytes, checksum: 07cd01b4a104f262986c24bd2a7f874b (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Neste trabalho realizamos a polarização térmica em vidros silicatos com composição (%mol) 22Na2O.8CaO.65SiO2 .5MO2 (M = Si, Ti, Ge, Zr, Sn e Ce). A polarização térmica consiste em aplicar um campo elétrico DC de elevada intensidade (~1 MV/m) em amostras a altas temperaturas. Durante a polarização térmica é gerado um campo elétrico permanente no interior da amostra, na região do anodo, que é responsável por propriedades ópticas nãolineares. Submetemos à polarização térmica amostras dos vidros, com ~1,5 mm de espessura e área de 20 x 20 mm2. Utilizamos eletrodos de Au, com diâmetro de 1 cm. As amostras foram aquecidas no interior de um forno até ~145 oC e aplicamos um campo elétrico de 1 MV/m durante 60 min. Durante a aplicação do campo elétrico, medimos simultaneamente a corrente através do circuito e as temperaturas no forno e na amostra. A corrente elétrica medida no circuito está relacionada com a migração de íons Na+ no interior das amostras do anodo para o catodo. A diminuição da corrente após um determinado tempo de polarização é devido à formação de uma camada com ausência de íons Na+ (camada de depleção) junto ao anodo. Os diferentes cátions tetravalentes, M4+, inseridos no vidro têm funções particulares na estrutura deste e afetam de formas distintas a corrente elétrica. A energia de ativação para a condutividade elétrica em vidros soda-cal-sílica está associada à energia necessária para o íon Na+ transpor a barreira de potencial entre os interstícios adjacentes na rede vítrea. Para determinar a energia de ativação da condutividade elétrica DC, Eσ, destes vidros, submetemos amostras de cada composição a um campo elétrico de 1 MV/m, durante 2 segundos para diferentes temperaturas entre 100 e 220 ºC. Esta energia está relacionada com... / In this work we performed thermal poling in glasses with composition (%mol) 22Na2O.8CaO.65SiO2 .5MO2 (M = Si, Ti, Ge, Zr, Sn and Ce). The thermal poling consist in apply a high intensity DC electric field (~1 MV/m) on samples at high temperatures. During the thermal poling process a permanent electric field is generated in the anode region of the sample, and this field is responsible for nonlinear optical properties of various glasses. We submit to thermal poling samples with ~1.5 mm in thickness and area of 20x20 mm2. We used gold electrodes with a diameter of 1 cm. The samples were heated inside a furnace to ~ 145 oC and an electric field of 1 MV/m was applied for 60 min. During the poling process, we measure simultaneously the current through the circuit and the temperatures in the furnace and of the sample. The electric current of the circuit is related to the migration of sodium ions in the bulk samples from the anode to the cathode. The current decrease with the poling time is due to the formation of a Na+ absent layer (depletion layer) near the anode surface. The different tetravalent cations, M4+, in the glass have different functions in their structures and affect the electrical current in particular manners. The activation energy for electrical conductivity in soda-lime-silica glasses is associated with energy for the Na+ ions to cross the potential barrier, which is submitted to the interstices of the glassy network, and jump into the nearest interstice. The activation energy of DC electrical conductivity, Eσ, of our samples of was determined by applying an electric field of 1 MV/m for 2 seconds, at different temperatures between 100 and 220 ºC. This energy is related to the current, I, through the equation ... The energy calculated is ~0.8 eV. To evaluate the structural and compositional changes of the samples surfaces that were in contact with the ...

Orientador: Ervino Carlos Ziemath / Banca: Dante Luis Chinaglia / Banca: Victor Ciro Solano Reynoso / Resumo: Neste trabalho realizamos a polarização térmica em vidros silicatos com composição (%mol) 22Na2O.8CaO.65SiO2 .5MO2 (M = Si, Ti, Ge, Zr, Sn e Ce). A polarização térmica consiste em aplicar um campo elétrico DC de elevada intensidade (~1 MV/m) em amostras a altas temperaturas. Durante a polarização térmica é gerado um campo elétrico permanente no interior da amostra, na região do anodo, que é responsável por propriedades ópticas nãolineares. Submetemos à polarização térmica amostras dos vidros, com ~1,5 mm de espessura e área de 20 x 20 mm2. Utilizamos eletrodos de Au, com diâmetro de 1 cm. As amostras foram aquecidas no interior de um forno até ~145 oC e aplicamos um campo elétrico de 1 MV/m durante 60 min. Durante a aplicação do campo elétrico, medimos simultaneamente a corrente através do circuito e as temperaturas no forno e na amostra. A corrente elétrica medida no circuito está relacionada com a migração de íons Na+ no interior das amostras do anodo para o catodo. A diminuição da corrente após um determinado tempo de polarização é devido à formação de uma camada com ausência de íons Na+ (camada de depleção) junto ao anodo. Os diferentes cátions tetravalentes, M4+, inseridos no vidro têm funções particulares na estrutura deste e afetam de formas distintas a corrente elétrica. A energia de ativação para a condutividade elétrica em vidros soda-cal-sílica está associada à energia necessária para o íon Na+ transpor a barreira de potencial entre os interstícios adjacentes na rede vítrea. Para determinar a energia de ativação da condutividade elétrica DC, Eσ, destes vidros, submetemos amostras de cada composição a um campo elétrico de 1 MV/m, durante 2 segundos para diferentes temperaturas entre 100 e 220 ºC. Esta energia está relacionada com... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: In this work we performed thermal poling in glasses with composition (%mol) 22Na2O.8CaO.65SiO2 .5MO2 (M = Si, Ti, Ge, Zr, Sn and Ce). The thermal poling consist in apply a high intensity DC electric field (~1 MV/m) on samples at high temperatures. During the thermal poling process a permanent electric field is generated in the anode region of the sample, and this field is responsible for nonlinear optical properties of various glasses. We submit to thermal poling samples with ~1.5 mm in thickness and area of 20x20 mm2. We used gold electrodes with a diameter of 1 cm. The samples were heated inside a furnace to ~ 145 oC and an electric field of 1 MV/m was applied for 60 min. During the poling process, we measure simultaneously the current through the circuit and the temperatures in the furnace and of the sample. The electric current of the circuit is related to the migration of sodium ions in the bulk samples from the anode to the cathode. The current decrease with the poling time is due to the formation of a Na+ absent layer (depletion layer) near the anode surface. The different tetravalent cations, M4+, in the glass have different functions in their structures and affect the electrical current in particular manners. The activation energy for electrical conductivity in soda-lime-silica glasses is associated with energy for the Na+ ions to cross the potential barrier, which is submitted to the interstices of the glassy network, and jump into the nearest interstice. The activation energy of DC electrical conductivity, Eσ, of our samples of was determined by applying an electric field of 1 MV/m for 2 seconds, at different temperatures between 100 and 220 ºC. This energy is related to the current, I, through the equation ... The energy calculated is ~0.8 eV. To evaluate the structural and compositional changes of the samples surfaces that were in contact with the ... / Mestre

This thesis explores the use of nonlinear crystals from theKTiOPO4(KTP) family with the aim to extend the possibleapplications for laser sources and to gain more knowledge aboutthe material’s benefits and limits. The work focussed onoptical parametric oscillators (OPOs) and optical parametricamplifiers (OPAs), which employ second order nonlinearprocesses. Both devices transfer energy from a laser beam at aparticular wavelength to a different wavelength, which istuneable. In OPOs two new beams at different wavelengths aregenerated, whereas in OPAs an existing weak beam is amplified.The essential part of these devices, which enables theoccurrence of the energy conversion, is a nonlinear crystal. Inthis work the ferroelectric crystals KTP and RbTiOPO4(RTP) have been utilized. By modifying the material’s structure,quasi-phasematching can be obtained, which is a crucialrequirement for achieving efficient energy conversion betweenthe incident and the generated waves. The fabrication ofquasi-phasematched crystals is dependent on the controlledreversion of the material’s spontaneous polarisation,which is accomplished by periodic electric field poling. Nanosecond pulses of more than 200 kW were generated in the“eye-safe”region by employing a double pass OPA.Small signal gains exceeding 75 dB were obtained for anessentially diffraction limited beamwithout spectralbroadening of the seed. By subsequent signal coupling intofibres substantial broadening was accomplished. A systematicmeasurement series of several RTP crystals allowed us toaccurately determine the wavelength and temperature dispersionof the refractive index, which are two essential requirementsfor further employment of this material. The OPOs based on RTPwere widely tuneable by controlling the temperature. It wasalso concluded that RTP behaves similar to KTP in parametricdevices, thus being a material, which can sustain high powers,possesses large nonlinear coefficients and can operate in abroad wavelength region.Efficient Raman oscillation concurrent with parametricoscillation was observed and analysed in several KTP samples.This gave further insight into the processes taking placeinside the material when performing as a frequency converter,if the generated idler lies in the absorption band.This thesis also covers the investigation of afemtosecond optical parametric chirped pulse amplifier.Temporally stretched seed pulses were amplified to 85 µJ,resulting in a gain above 60 dB, and subsequent recompressionresulted in 270 fs pulses. <b>Keywords:</b>nonlinear optics, KTiOPO4, optical parametric oscillator, optical parametricamplifier, RbTiOPO4, quasi-phasematching, electric field poling,stimulated Raman scattering. / NR 20140805

This thesis presents the fabrication of a low loss hybrid waveguide electric field(E-field) sensor based on optical D-fiber. This novel E-field sensor is formed as part of a contiguous fiber resulting in a flexible and small cross-section device that can be embedded into electronic circuitry. The in-fiber nature of this sensor also eliminates the need for alignment and packaging that conventional sensors need. An optical fiber can detect electric fields when the core of the fiber is partially removed and replaced with an electro-optic polymer. This polymer causes a change in the index of refraction in the waveguide of the device when in the presence of an electric field. The change in the effective index of refraction changes the speed of the light in the vertical axis relative to the light in the horizontal axis creating a phase change between the two axes. This phase change can be detected as a change in the polarity of the light coming out of the fiber. The sensor is formed by partially etching out the core of a D-shaped optical fiber and depositing a polymer to form a hybrid waveguide. The polymer becomes sensitive to electric fields through corona poling. The typical corona poling process is not amenable to poling a polymer located in the fiber core. A method of poling conducive to an in-fiber device was developed and demonstrated. Using PMMA and DR1 for proof of concept, the operation of the first in-fiber hybrid waveguide electric field sensor is demonstrated. Etch depth, polymer composition, and polymer spin rate are optimized to provide strong interaction between the light and the sensing portion of the hybrid waveguide while maintaining low optical loss. High frequency testing was demonstrated to show that the effect is electro-optic. AC testing also allows the Epi of the sensors to be determined at lower electric fields than are required for DC testing, eliminating charge build up and electric field break down issues.

Syfte Studien syftar till att klarlägga hur stavisättningen och stakfasen påverkas vid användandet av en böjd jämfört med en rak stavdesign vid stakning i hög hastighet på rullskidor på rullband. Följande frågeställningar har undersökts:  Leder en böjd stavdesign till att stavisättningen sker längre fram?  Leder en böjd stavdesign till att stakfasens absoluta längd förändras?  Leder en böjd stavdesign till att stakfasens relativa längd förändras? Metod Tio manliga längdskidåkare (ålder 25,3 ± 5,1 år, kroppslängd 182,1 ± 8,6 cm, kroppsvikt 78 ± 6,5 kg) deltog i studien. Forskningspersonerna genomförde ett Vmax-protokoll stakning på rullskidor på rullband, med rak såväl som med böjd stavdesign. Rörelsedata samlades in och analyserades för att fastställa eventuella skillnader i stavisättning, stakfas, återförandefas och total cykeltid. Resultat En signifikant skillnad kan påvisas gällande stavisättning, där en böjd stavdesign leder till en stavisättning längre framför bindningen jämfört med en rak stavdesign. Ingen signifikant skillnad kan påvisas rörande stakfasen, återförandefasen eller total cykeltid. Slutsatser Studiens visar att stavspetsens rörelsebana flyttas vid nyttjande av en böjd stavdesign i riktning framåt. Dock påverkas inte stakfasen, återförandefasen eller total cykeltid, vilket innebär att stakfasens längd, i absoluta såväl som relativa termer, är densamma vid stakning med rak och böjd stavdesign. / Purpose statement The purpose of the study is to examine how the pole plant and pole phase are affected by using a pole of curved, compared to straight, design for double poling at high speed on roller skis at a treadmill. The following research questions have been examined:  Does a curved pole design result in a pole plant further forward?  Does a curved pole design result in a change in the absolute length of the pole phase?  Does a curved pole design result in a change in the relative length of the pole phase? Methodology Ten male cross country skiers (age 25,3 ± 5,1 years, height 182,1 ± 8,6 cm, BW 78 ± 6,5 kg) took part in the study. The test subjects performed a Vmax-test double poling on roller skis on a treadmill, with straight and curved poles. Movement data was collected and analysed to examine potential differences regarding pole plant, pole phase, recovery phase and total cycle time. Results A significant difference was found regarding the pole plant, as a curved pole design resulted in a pole plant further forward compared to a straight design. No significant difference was found related to the pole phase, recovery phase or total cycle time. Conclusion The study shows that the path of the pole tip is moved forward when using poles of a curved design. There is no change in the pole phase, the recovery phase or the total cycle time, thus the length of the pole phase, absolute as well as relative, is unaffected by pole design when double poling.

Introduction Researchers have, for decades, contributed to an increased collective understanding of the physiological demands in cross-country skiing; however, almost all of these studies have used either non-elite subjects and/or performances that emulate cross-country skiing. To establish the physiological demands of cross-country skiing, it is important to relate the investigated physiological variables to the competitive performance of elite skiers. The overall aim of this doctoral thesis was, therefore, to investigate the external validity of physiological test variables to determine the physiological demands in competitive elite cross-country skiing. Methods The subjects in Study I – IV were elite male (I – III) and female (III – IV) cross-country skiers. In all studies, the relationship between test variables (general and ski-specific) and competitive performances (i.e. the results from competitions or the overall ski-ranking points of the International Ski Federation (FIS) for sprint (FISsprint) and distance (FISdist) races) were analysed. Test variables reflecting the subject’s general strength, upper-body and whole-body oxygen uptake, oxygen uptake and work intensity at the lactate threshold, mean upper-body power, lean mass, and maximal double-poling speed were investigated. Results The ability to maintain a high work rate without accumulating lactate is an indicator of distance performance, independent of sex (I, IV). Independent of sex, high oxygen uptake in whole-body and upper-body exercise was important for both sprint (II, IV) and distance (I, IV) performance. The maximal double-poling speed and 60-s double-poling mean power output were indicators of sprint (IV) and distance performance (I), respectively. Lean mass was correlated with distance performance for women (III), whereas correlations were found between lean mass and sprint performance among both male and female skiers (III). Moreover, no correlations between distance performance and test variables were derived from tests of knee-extension peak torque, vertical jumps, or double poling on a ski-ergometer with 20-s and 360-s durations (I), whereas gross efficiency while treadmill roller skiing showed no correlation with either distance or sprint performance in cross-country skiing (IV). Conclusion The results in this thesis show that, depending on discipline and sex, maximal and peak oxygen uptake, work intensity at the lactate threshold, lean mass, double-poling mean power output, and double-poling maximal speed are all externally valid physiological test variables for evaluation of performance capability among elite cross-country skiers; however, to optimally indicate performance capability different test-variable expressions should be used; in general, the absolute expression appears to be a better indicator of competitive sprint performance whereas the influence of body mass should be considered when evaluating competitive distance performance capability of elite cross-country skiers.

<p>The topic of this thesis is development ofdevices fortelecom applications based on poled optical fibers. The focusis on two different specific functions, wavelength conversionand optical switching.</p><p>Optical switching is demonstrated in a poled optical fiberat telecom wavelengths (~1.55 mm). The fiber has two holesrunning along the core in which electrodes are inserted. Thefiber device is made electro-optically active with a polingprocess in which a strong electric field is recorded in thefiber at a temperature of 270 o C. The fiber is then put in onearm of a Mach-Zehnder interferometer and by applying a voltageacross the two electrodes in the fiber the refractive index ismodulated and the optical signal switched from one output portto the other. So far the lowest switching voltage achieved is~1600 V which is too high for a commercial device, but byoptimizing the design of the fiber and the poling process aswitching voltage as low as 50 V is aimed for.</p><p>A method to deposit a thin silver electrode inside the holesof an optical fiber is also demonstrated. A new way of creatingperiodic electrodes by periodically ablating the silver filmelectrode inside the holes of an optical fiber is also shown.The periodic electrodes can be used to create a quasi-phasematched (QPM) nonlinearity in the fiber which is useful forincreasing the efficiency of a nonlinear process such aswavelength conversion. Poling of a fiber with silver electrodesshowed a huge increase in the nonlinearity. This could be dueto a resonant enhancement caused by silver nanoclusters.</p><p><b>Keywords:</b>Poling, twinhole fiber, fiber electrodes,silver film electrodes, silver diffusion, quasi-phase matching,optical switching, frequency conversion, optical modulation</p>

Fine-pitch ferroelectric domain gratings are extensively used for generation of light in the visible and near-infrared spectral regions through quasi-phase matched (QPM) frequency conversion. Sub-μm QPM devices enables demonstration of nonlinear optics with counterpropagating waves, a field of nonlinear optics which remains sparsely explored due to the difficulty of fabricatinghigh quality gratings. In recent years, bulk Rb-doped KTiOPO4 (RKTP) has emerged as a highly promising nonlinear materials for fabrication of fine-pitch QPM devices through periodic electric-field poling. RKTP possesses large optical nonlinearity and high resistance to optical damage, while demonstrating improved material homogeneity and lower ionic conductivity than its isomorphs, which are important features for poling. Although fine-pitch QPM gratings, as well as large aperture QPM devices, have been demonstrated, fabrication of sub-μm high quality QPM devices remains a challenge. The primary aim of this research was to develop a reliable method to fabricate high-quality sub-μm periodically poled RKTP crystals (PPRKTP) and exploit them in novel optical applications. For this purpose, a novel poling method was developed. It was based on periodic modulation of the coercive field through ion exchange, where K+ ions are exchanged with Rb+ in the crystal, to modulate the coercive field and the ionic conductivity. This enables periodic poling of higher quality and with shorter period than ever before. High quality PPRKTP with a period of 755 nm were fabricated and used to demonstrate the first cascaded mirrorless optical parametric oscillator (MOPO), as well as the first MOPO pumped by a Q-switched laser. PPRKTP samples for blue light generation were fabricated, and second harmonic generation (SHG) was investigated with a high power 946 nm fiber laser. Up to 2 W of blue power was demonstrated for bulk samples, where the output power was limited by absorption of the SHG, leading to thermal dephasing of the devices. Laser-written waveguides were fabricated in PPRKTP for the first time, and a record high SHG power of 76 mW was obtained. Finally, the high-temperature stability of ferroelectric domain gratings was investigated. This is of utmost importance when a PPRKTP crystal is used as a seed for crystal growth. It was found that for charged domains walls, the domain-wall motion was highly anisotropic with rapid movement in y-direction while only small movements were observed in the x-direction of the crystal. / Ickelinjära ferroelektriska kristaller med artificiella domängitter med perioder av några mikrometer används idag för generering av ljus i de synliga och nära-infraröda våglängdsområdena, genom kvasifasmatchad (QPM) frekvenskonvertering. Med sub-μm QPM domängitter kan man åstadkomma ickelinjära optiska effekter med motpropagerande parametriska ljusvågor. Detta är ett område av den ickelinjära optiken som fortfarande är tämligen outforskat på grund av svårigheten med att tillverka högkvalitativa domängitter.  Under de senaste åren har Rb-dopat KTiOPO4 (RKTP) blivit ett mycket lovande ickelinjärt material för tillverkning av QPM-gitter med mycket korta perioder genom periodisk elektrisk fält polning. RKTP kristallen har en hög optisk ickelinejäritet och den tål höga optiska intensiteter, samtidigt som materialet har bättre materialhomogenitet och lägre jonledningsförmåga än vad dess isomorfa kristaller har. De två senare egenskaperna har visat sig viktiga för att få en lyckad polning. Fastän QPM-gitter med kort periodicitet, liksom QPM-gitter med stor apertur, har demonstrerats, är tillverkningen av högkvalitativa QPM-kristaller med sub-µm perioder fortfarande en utmaning. Det primära syftet med denna avhandling var att utveckla en pålitlig metod för att tillverka högkvalitativa sub-μm periodiskt polade RKTP kristaller (PPRKTP) och utnyttja dem i nya optiska tillämpningar. I detta syfte utvecklades en ny polningsmetod. Den baseras på periodiskt jonutbyte, där K+ joner byts mot Rb+ i kristallen, vilket resulterar i en samtidig modulation av materialets koerciva fält och jonledningsförmåga. Detta möjliggör i sin tur periodisk polning av högre kvalitet och med kortare perioder än någonsin tidigare har uppnåtts. Högkvalitativa PPRKTP kristaller med en period på 755 nm tillverkades och användes för att demonstrera den första kaskaderade spegelfria optiska parametriska oscillatorn (MOPO), liksom den första MOPO processen pumpad av en Q-switchad laser. Vidare utvecklades PPRKTP-kristaller för generering av blått ljus via frekvensdubbling. Dessa utvärderades med hjälp av en högeffekts-fiberlaser vid 946 nm. Upp till 2 W av blått ljus erhölls för bulkkristallerna. Uteffekten begränsades av absorption av det blåa frekvensdubblade ljuset, vilket ledde till urfasning i QPM-gittret p.g.a. termiska effekter. Laserskrivna vågledare tillverkades sedan i PPRKTP för första gången, och en rekordhög effekt på 76 mW erhölls via frekvensdubbling. Slutligen undersöktes stabiliteten hos de periodiskt polade domängitterna vid höga temperaturer. Det är viktigt att domängittrena är stabila när PPRKTP kristallerna används som ympämne för kristalltillväxt. Det visade sig att instabila domänväggar flyttade sig mycket anisotropt, med en snabb rörelse i kristallens y-riktning och en långsam rörelse i kristallens x-riktning. / <p>QC 20170519</p>