Laser Level Research Articles

The Precision, Inter-Rater Reliability, and Accuracy of a Handheld Scanner Equipped with a Light Detection and Ranging Sensor in Measuring Parts of the Body-A Preliminary Validation Study.

Anthropometric measurements play a crucial role in medico-legal practices. Actually, several scanning technologies are employed in post-mortem investigations for forensic anthropological measurements. This study aims to evaluate the precision, inter-rater reliability, and accuracy of a handheld scanner in measuring various body parts. Three independent raters measured seven longitudinal distances using an iPad Pro equipped with a LiDAR sensor and specific software. These measurements were statistically compared to manual measurements conducted by an operator using a laser level and a meterstick (considered the gold standard). The Friedman test revealed minimal intra-rater variability in digital measurements. Inter-rater variability analysis yielded an ICC = 1, signifying high agreement among the three independent raters. Additionally, the accuracy of digital measurements displayed errors below 1.5%. Preliminary findings demonstrate that the pairing of LiDAR technology with the Polycam app (ver. 3.2.11) and subsequent digital measurements with the MeshLab software (ver. 2022.02) exhibits high precision, inter-rater agreement, and accuracy. Handheld scanners show potential in forensic anthropology due to their simplicity, affordability, and portability. However, further validation studies under real-world conditions are essential to establish the reliability and effectiveness of handheld scanners in medico-legal settings.

Modeling with graded interfaces: Tool for understanding and designing record-high power and efficiency mid-infrared quantum cascade lasers

Abstract By employing a graded-interfaces model based on a generalized formalism for interface-roughness (IFR) scattering that was modified for mid-infrared emitting quantum cascade lasers (QCLs), we have accurately reproduced the electro-optical characteristics of published record-performance 4.9 µm- and 8.3 µm-emitting QCLs. The IFR-scattering parameters at various interfaces were obtained from measured values and trends found via atom-probe tomography analysis of one of our 4.6 μm-emitting QCL structures with variable barrier heights. Those values and trends, when used for designing a graded-interface, 4.6 μm-emitting QCL, led to experimental device characteristics in very good agreement with calculated ones. We find that the published record-high performance values are mainly due to both injection from a prior-stage low-energy (active-region) state directly into the upper-laser (ul) level, thus at low field-strength values, as well as to strong photon-induced carrier transport. However, the normalized leakage-current density J leak /J is found to be quite high: 26–28 % and 23.3 %, respectively, mainly because of IFR-triggered shunt-type leakage through high-energy active-region states, in the presence of high average electron temperatures in the ul laser level and an energy state adjacent to it: 1060 K and 466 K for 4.9 µm- and 8.3 µm-emitting QCLs, respectively. Then, modeling with graded interfaces becomes a tool for designing devices of performances superior to the best reported to date, thus closing in on fundamental limits. The model is employed to design a graded-interface 8.1 µm-emitting QCL with suppressed carrier leakage via conduction-band engineering, which reaches a maximum front-facet wall-plug efficiency value of 22.2 %, significantly higher than the current record (17 %); thus, a value close to the fundamental front-facet, upper limit (i.e., 25 %) for ∼8 µm-emitting QCLs.

Extraction of the electron excess temperature in terahertz quantum cascade lasers from laser characteristics

Abstract We propose a method to extract the upper laser level’s (ULL’s) excess electronic temperature from the analysis of the maximum light output power (P max) and current dynamic range ΔJ d = (J max − J th) of terahertz quantum cascade lasers (THz QCLs). We validated this method, both through simulation and experiment, by applying it on THz QCLs supporting a clean three-level system. Detailed knowledge of electronic excess temperatures is of utmost importance in order to achieve high temperature performance of THz QCLs. Our method is simple and can be easily implemented, meaning an extraction of the excess electron temperature can be achieved without intensive experimental effort. This knowledge should pave the way toward improvement of the temperature performance of THz QCLs beyond the state-of-the-art.

НАБЛЮДЕНИЯ ЗА ДЕФОРМАЦИЯМИ СООРУЖЕНИЙ В ЗОНЕ СТРОИТЕЛЬСТВА МЕТРОПОЛИТЕНА Г. АЛМАТЫ

The article presents the results of monitoring the condition of surface buildings and structures during the construction and operation of the Almaty metro located within a radius of 80 meters. In such a situation, the problem of managing geodynamic processes during the construction and operation of the subway can be solved on the basis of the methodology of conducting geodetic monitoring of the condition of engineering structures considered in this article. It is shown that when conducting geodetic monitoring and monitoring of deformations of engineering structures using modern geodetic instruments such as global navigation satellite systems, electronic total stations, laser levels, it will allow obtaining information about the ongoing deformation processes of buildings and structures located in close proximity to the metro under construction and in operation with a high degree of accuracy, which will ensure timely management decisions solutions for long-term and safe operation.

The Impact of Dermal Characteristics on Low‐Level Laser Power Measurement in Postmortem Zoological Species

Photobiomodulation therapy, also termed as low‐level laser therapy, is commonly used as an adjunctive therapy for various medical conditions in veterinary practice. The ACTIVet PRO low‐level laser has been used for treatment of various nondomestic species, yet the effects of dermal attributes such as pigment, feathers, or scales have not been evaluated. The effects of low‐level laser therapy with the ACTIVet PRO have been investigated in laboratory animals, including a study in rats that evaluated the passage of laser light through the skin in postmortem samples. The objective of this study was to measure the power of a low‐level laser (ACTIVet PRO) after penetration through dermal tissue (∼1 mm thickness) in a variety of postmortem animal tissue. This study sought to determine the impact of fur, feathers, scales, and different pigments on the ability of the laser to penetrate. Frozen and thawed skin tissue samples from various species were placed inside a light restricted laser box and exposed to a preprogrammed laser level from a Multi Radiance ACTIVet PRO photobiomodulation (PBM) device, with a power meter to measure the light penetration through the tissue samples. Light penetration measurements via power output measurements (mW) were recorded at 7 time points (range, 1–150 sec). A Friedman test was performed to evaluate the difference of the mean tissue penetration by each species at each time point. Lighter colored specimens had higher power readings than darker colored or pigmented samples, and feathers appeared to inhibit the laser, showing minimal to no power readings on bird skin covered in covert and down feathers. There was statistically significant mean tissue penetration for all time points between the rabbit and green sea turtle (p = 0.0046), the red‐tailed hawk and green iguana (p = 0.0046), and the red‐tailed hawk and green sea turtle (p = 0.000034). Overall findings found that certain skin coverings, such as feathers, appear to inhibit passage of laser light through tissue to the photo meter. Darker pigmented areas of tissue appeared to absorb the laser light, which also did not allow light passage through the tissue to the photo meter. All of this illustrates that there are differences in tissue penetration between different animal species, at least in postmortem tissues. This could necessitate adjustment of machine settings for therapeutic effect in different species, though further studies would be warranted to determine the extent to which this would be necessary. Additional studies evaluating biologically active tissues would be needed as a next step, as photobiomodulation has an effect at the cellular level and the exact amount of medical benefit is not measurable in skin samples that are separate from a living organism.

Effect of Leveling and Tillage Equipment on Soil Bulk Density and Yield of Maize

A field experiment was carried out to evaluate the effect of leveling and tillage equipment on the soil bulk density and the growth and production of maize. Three landscaping types of equipment, namely laser, pelvic, and grader equipment, and three tillage equipment, namely moldboard plow, chisel plow, and no-till farming system. Soil bulk density, practical productivity, plant height, weight of 100 seeds, number of seeds per ear, and the yield of maize were measured. The results can be summarized as follows: The interaction between the pelvic leveling equipment and the no-till farming system was superior in obtaining the lowest soil bulk density, while the interaction between the laser leveling equipment and chisel plow was superior in obtaining the highest plant height, the highest weight of 100 seeds stood 36.70 g, the highest number Seeds per ear stood 371.30 seeds per ear and the highest yield of the plant stood 6.36 tons ha-1 compared to the other interventions.

Stationary High-Energy Pulse Generation in Er-Based Fiber Lasers via Quasi-Synchronous Gain Modulation

We demonstrate the feasibility of triggering stationary high-energy pulse generation in Er-doped fiber lasers at ~1.5 µm via quasi-synchronous gain modulation. This simple method relies upon the sine-wave modulation of pump power at a frequency slightly surpassing the intrinsic frequency spacing of longitudinal modes in the laser cavity. This was previously implemented only in Yb-doped fiber lasers at ~1.1 µm. Here, for the first time, we experimentally validate the pulse shaping capabilities of this method also in Er fiber lasers, which, unlike Yb fiber lasers, have a three-level laser energy diagram (when pumped at 0.98 µm) with a very long-lived (10 ms) upper laser level. The feasibility of the method was validated both for normal and anomalous intracavity dispersion, which was not available in previous implementations in Yb fiber lasers at ~1.1 µm. Thus, the stable generation of a regular train of discrete nanosecond pulses with an energy of up to 180 nJ was achieved in our test-bed Er fiber laser upon the quasi-synchronous sine-wave modulation of the pump power at 0.98 µm. The results of our study testify to the general applicability of this affordable and reliable method for high-energy pulse generation in various rare-earth-doped fiber lasers.

Growth and efficient laser emission of Er3+ doped LGGG single crystal at 2.8 μm

A novel kind of high-quality Er3+:LGGG crystal has been grown using the Czochralski method and exhibited excellent lasing performance for the first time at around 2818 nm in the mid-infrared spectral region. The J-O intensity parameters, spontaneous emission probability, branching ratio, and exited state lifetimes parameters have been calculated for the first time using the J-O theory, providing theoretical references for future analysis of the absorption and emission characteristics of Er3+:LGGG crystals. The fluorescence lifetimes of the upper (4I11/2) and lower (4I13/2) laser levels are 1.42 and 5.18 ms, respectively. Under 976 nm laser pumping, a continuous-wave laser output of 374 mW with excellent beam quality factors Mx2/My2 of 1.374/1.228 has been achieved by using the Er3+:LGGG crystal. These results indicate that Er3+:LGGG crystals are promising materials for generating 2.8 μm mid-infrared lasers.

Water productivity of barley crop under laser land leveling technique and minimum tillage

ABSTRACTLaser land leveling is an important method that helps to improve the spatial distribution of irrigation water and fertilizers applications, subsequently reduce water, nutrient, and energy inputs to agriculture and contributes to increasing productivity. Thus, the aim of the study was to improve the productivity of the barley crop grown in sandy lands under conditions of water scarcity and the negative impact of climate change in Egypt by using laser leveling and the minimum tillage method. Two experiments were conducted during the 2020/2021 and 2021/2022 seasons at the Nubariya farm, Buhaira Governorate, Egypt to study the effects of laser leveling and minimum tillage (zero – tillage, 10 cm, 20 cm, and 30 cm) affecting the distribution of soil moisture, water stress, effectiveness of water application, yield characteristics, water productivity, and some quality parameters of the barley crop. The statistical analysis’ findings revealed a considerable influence of both laser soil leveling and minimum depth of plowing on productivity, water productivity and quality properties of barley crop. Laser leveling with a plowing depth of 10 cm gave the most favorable values of the soil moisture content at the root-zone as well as better grain yield and water productivity in addition to improve the quality properties of barley. The grain yield has improved by 12.65% and 10.41%, while water productivity has increased by 12.75% and 10.06% during the seasons 2020/2021 and 2021/2022, respectively. This increase is likely the result of improving soil moisture distribution and increasing irrigation application efficiency, which resulted in less water stress in the root zone and subsequently increased yield, water productivity and quality properties of barley during the two growing seasons. Generally, the application of laser land leveling as eco-friendly practice will help in sustaining barley productivity in Egypt particularly in the sandy soil regions. According to this study, laser-assisted precision field leveling has the potential to improve grain yield and crop establishment, water productivity and barley quality properties in addition to achievement of the highest net income for farmers.

Pump quantum efficiency optimization of 3.5 μm Er-doped ZBLAN fiber laser for high-power operation

976 nm + 1976 nm dual-wavelength pumped Er-doped ZBLAN fiber lasers are generally accepted as the preferred solution for achieving 3.5 μm lasing. However, the 2 μm band excited state absorption from the upper lasing level (4F9/2 → 4F7/2) depletes the Er ions population inversion, reducing the pump quantum efficiency and limiting the power scaling. In this work, we demonstrate that the pump quantum efficiency can be effectively improved by using a long-wavelength pump with lower excited state absorption rate. A 3.5 μm Er-doped ZBLAN fiber laser was built and its performances at different pump wavelengths were experimentally investigated in detail. A maximum output power at 3.46 μm of ~ 7.2 W with slope efficiency (with respect to absorbed 1990 nm pump power) of 41.2% was obtained with an optimized pump wavelength of 1990 nm, and the pump quantum efficiency was increased to 0.957 compared with the 0.819 for the conventional 1976 nm pumping scheme. Further power scaling was only limited by the available 1990 nm pump power. A numerical simulation was implemented to evaluate the cross section of excited state absorption via a theoretical fitting of experimental results. The potential of further power scaling was also discussed, based on the developed model.Graphical

Climate-smart agriculture strategies for South Asia to address the challenges of climate change: Identification of climate-resilient agriculture practices for India, Bangladesh, and Afghanistan

In South Asia, agriculture is pivotal for food and nutritional security and the livelihood of more than 50% of the population. Food production and nutritional security pressures intensify as urbanisation decreases the agricultural land area amid population growth. Climate change complicates this scenario by introducing elevated temperatures, extreme climatic events, surging sea levels, and increased soil salinity. Identifying climate-resilient innovative technologies for farmer adoption becomes imperative to counter these adversities. An integrated approach to climate-smart agriculture, encompassing capacity building through practical training on innovative mitigation strategies, is needed. This study unites experts from Australia, India, Bangladesh, and Afghanistan in an Asia-Pacific Network project, fostering mutual learning and farmer training in climate-smart practices. Insights from workshops conducted at Amity University in February 2020 and June 2022, combined with country-specific technological advances in the past 15 years gleaned from the literature, revealed key technologies to combat climate change (e.g., zero tillage, raised bed planting, direct-seeded rice, crop residue management, crop diversification, site-specific nutrient management, laser levelling, micro-irrigation, seed/fodder banks, and ICT-based weather advisories). Widespread implementation of these technologies and practices will empower farmers to navigate climate change challenges, fostering resilience and sustainability.

Benefit of Tb3+ ions to the spectral properties of Dy3+/Tb3+:CaYAlO4 crystal for use in yellow laser

Single crystals of Dy3+ single-doped and Dy3+/Tb3+ co-doped CaYAlO4 are grown and analyzed. In comparison to Dy3+:CaYAlO4, the absorption cross sections around 453 nm and emission cross section at 582 nm acquired a growth after the incorporation of Tb3+. The fluorescence lifetimes of Dy3+:4F9/2 upper and Dy3+:6H13/2 lower laser levels for 582 yellow emission fall from 0.293 ms to 0.070 ms–0.285 ms and 0.018 ms, respectively. The fluorescence branching ratios of yellow emission at 582 nm are 49.2% and 50.733% for Dy3+:CaYAlO4 and Dy3+/Tb3+:CaYAlO4 crystals, respectively. Deactivation effect of Tb3+ ions as well as the energy transfer mechanism in Dy3+/Tb3+:CaYAlO4 crystal are discussed in detail, and the temperature dependent spectra of the two crystals are also studied as well. Those results indicate that the introduction of deactivation ion Tb3+ can be beneficial for achieving an enhanced yellow emission in Dy3+/Tb3+:CaYAlO4.

Study on thermal effect and electro-optically Q-switching of Cr, Tm, Ho: YAG laser

The thermal effect and Q-switching of flashlamp-pumped Cr, Tm, Ho: YAG (CTH: YAG) laser were investigated systematically. The fraction of pump power dissipated as heat in flashlamp-pumped CTH: YAG laser system was evaluated for the first time by measurements and calculations on thermal lens effect. The quasi-steady state and transient temperature distributions of laser rod were numerical simulated. In addition, Electro-optically Q-switching was studied by design of thermal effect compensation resonator. An unusual phenomenon that the optimal delay time of Q-switch in CTH: YAG was shorter than the pump duration was reported for the first time as far as we know. According to the experimental and theoretical calculation results, the main cause of the phenomenon is the long lifetime of lower laser level, followed by up-conversion and fluorescence quenching at high temperature. The mechanism proposed in this paper is of great significance for the design of highly efficient Q-switched CTH: YAG lasers.

Accuracy of intra-arterial line transducer levelling practice in a general intensive care unit

BackgroundThe intra-arterial line is a common device intervention used in the intensive care environment to provide continuous blood pressure measurement. The transducer line is levelled to the patient's phlebostatic axis to provide accurate measurements. AimThe aim of this study was to investigate registered nurses' accuracy at levelling the transducer to the correct anatomical position using visual judgement, compared to one done using a laser level. MethodsPatient transducers were levelled by visual judgement and then by using a laser level. Time and mean arterial pressure (MAP) were recorded with each measurement along with any difference in transducer level between the two methods and subsequent changes in inotrope administration. ResultsA total of 577 MAP measurements were recorded from 178 patients; 70% of observations had a difference in transducer level, 30% of the time the inotrope rate was increased and 18% of the time the inotrope rate was reduced. The prevalence of clinically significant observations with an absolute difference of 50 mm or more in transducer placement was 25%. The mean difference in MAP measurements when a cut-off of 64 mmHg or more for laser was applied to the data was 0.22 (95% confidence interval: −0.14, 0.58, n = 513, p = 0.23), and for a cut-off of less than 64 for laser, a larger mean difference of 4.36 (95% confidence interval: 3.75, 5.28], n = 64, p < 0.001) was observed. ConclusionsTransducers were unable to be accurately levelled for haemodynamic monitoring using visual means alone. Over the range of patient MAP values examined, 25% of all observations had a clinically significant absolute difference of 50 mm or more in the transducer level position between the two methods. The visual method became increasingly inaccurate and unreliable at low MAP levels requiring medical intervention.

An Experiment on Surface Fluctuation of Ga-In-Sn Alloy with a Permanent Magnet Flow Control Mold

To control well the surface fluctuation of liquid metal in a slab mold, a new type of combined permanent magnets braking system, namely a permanent magnet flow control mold (PMFC-Mold) is proposed by our research group, of which its main feature is that the device can control the flow of molten steel in the mold without additional energy. To observe the fluctuation state of the alloy with the PMFC-Mold, instantaneous surface fluctuations were recorded by a laser level meter and camera. To study the effect of various casting speeds and permanent magnet placement on surface fluctuations, the three measurement points, which were 7, 18, and 36 mm away from the narrow surface of the mold, were selected to record the trend of level fluctuation. Three types of permanent magnet placement were designed by setting the differences between the height center of the permanent magnet and the free surface in the slab mold, which were H1 = 0 mm, H2 = −25 mm, and H3 = −75 mm. The experimental results indicated that with the acceleration of the casting speed, the average height and standard deviation of surface fluctuation at the measurement point increased, but the surface fluctuation pattern remained. When the permanent magnets were arranged at H1 = 0 mm and H2 = −25 mm, the position of the magnetic field was reasonable and the surface fluctuation could be effectively suppressed. In contrast, when the permanent magnets were arranged at H3 = −75 mm, the level fluctuation was intensified.

Quantifying the energy use efficiency and greenhouse gas emissions in Punjab (India) agriculture

It is inevitable to acknowledge the greenhouse gas emissions (GHGE)’s primary role in the planet's rising temperatures, which poses threat to ecosystem's sustainability. In India, a 18% of the total GHGE comes from agriculture. Agricultural systems, being complex, need highly efficient energy usage to ensure better yields, and hence, farmer income and food security. Within India, Punjab is the state with greatest agro-economic impact. Therefore, present study is an attempt to quantify the GHGE and energy use efficiency (EUE) in major crops (cotton, maize, paddy, wheat, and sugarcane) of Punjab based on 2019–2020 data. Results revealed that the direct energy and non-renewable energy contribution significantly exceeded the indirect energy and renewable energy, in all crops except sugarcane. Electricity and fertilizers were noted as key areas for energy sink for all crops studied. The specific energy based on economic yield was realized to be significantly higher in cotton (10.23 MJ Kg−1), followed by paddy (5.28 MJ Kg−1), and less than 5 MJ Kg−1 for other crops. High energy intensity indicates that there exists a better potential for further improvement in the energy productivity of cropping systems. In terms of total input-output energy, net energy gain and EUE, sugarcane was noted to be at the top, followed by paddy among other seasonal crops. Paddy was found to emit the highest CO2 eq. emissions (6718 kg CO2 eq. ha−1) of all crops and around 60% was contributed solely by methane (CH4) due to paddy cultivation in submerged water. Thus, optimizing fertilizer rates, precisely guided irrigation systems, adoption of resource conservation technologies (RCTs) i.e., DSR, Laser leveling, minimizing crop residue burning, and using them for energy supply are among best possible alternatives for improving EUE and reducing GHGE.

Effect of Land Ploughing Methods and Leveling Techniques on Wheat Production in the Upper Terraces of the Northern State - Sudan

Precision land leveling must be treated as a precursor technology for improving crop yield, enhancing input-use efficiency and ensuring long-term sustainability of the resources. A field experiment was conducted in Dongola Agricultural Research Farm, Northern State, for two successive seasons to investigate the effect of three type of ploughing; heavy disc harrow (H1), disc plough (H2) and no-ploughing (H3), and three land leveling techniques, Laser (L), Scraper (S) and traditional (T),on wheat production. The experiment was arranged in a strip split plot design and the treatments were replicated three times.&#x0D; The results indicated that effective field capacity, fuel consumption, and slippage were significantly affected by ploughing method. Laser land leveling recorded the highest fuel consumption (16.3 L/hr), and the lowest field efficiency (55%). while the heavy disc harrow recorded the highest effective field capacity (0.98 ha/hr), field efficiency (71.2%) and wheel slippage (8.1%). The soil moisture content (db %) was increased with time and depth. The highest mean soil moisture content was obtained with the laser land leveling and heavy disc harrow treatment at 75-100cm soil depth as 24.82%. The results revealed that the highest average grain yield (4.63 ton/ha) and infiltration rate (31cm/hr) were also recorded by the laser land leveling and heavy disc harrow. The treatments showed significant differences at the 5% level between the treatments for the parameters measured. Multiple regression analysis showed a highly significant effect (P≤ 0.001) of laser leveling with disc harrow ploughing on grain yield, compared to the other treatments used in the study (R2 = 0.40). The relation between the grain yield (Y) and the treatments: X1 ploughing, X2 leveling is summarized in the following equation: &#x0D; Y = 2.875 + 0.552X1 + 0.254X2&#x0D; The study concluded that, although Laser leveling has increased the grain yield with high cost, yet it is not an expensive technique when the cost is distributed over the period of Laser leveling. The highest grain yield was obtained by the heavy disc harrow with laser land leveling.

Two-well injector direct-phonon terahertz quantum cascade lasers

We present an experimental study on a terahertz quantum cascade laser (THz QCL) design that combines both two-well injector and direct-phonon scattering schemes, i.e., a so-called two-well injector direct-phonon design. As a result of the two-well injector direct-phonon scheme presented here, the lasers benefit from both a direct phonon scattering scheme for the lower laser level depopulation and a setback for the doping profile that reduces the overlap of the doped region with active laser states. Additionally, our design also has efficient isolation of the active laser levels from excited and continuum states as indicated by negative differential resistance behavior all the way up to room temperature. This scheme serves as a good platform for improving the temperature performance of THz QCLs as indicated by the encouraging temperature performance results of the device with a relatively high doping level of 7.56 × 1010 cm−2 and Tmax ∼ 167 K. With the right optimization of the molecular beam epitaxy growth and interface quality, the injection coupling strength, and the doping density and its profile, the device could potentially reach higher temperatures than the latest records reached for the maximum operating temperature (Tmax) of THz QCLs.

M-plane GaN terahertz quantum cascade laser structure design and doping effect for resonant-phonon and phonon-scattering-injection schemes

Non-polar m-plane GaN terahertz quantum cascade laser (THz-QCL) structures have been studied. One is traditional three-well resonant-phonon (RP) design scheme. The other is two-well phonon scattering injection (PSI) design scheme. The peak gains of 41.8 and 44.2 cm−1 have been obtained at 8.2 and 7.7 THz respectively at 300 K according to the self-consistent non-equilibrium Green’s function calculation. Different from the usual GaAs two-well design, the upper and lower lasing levels are both ground states in the GaN quantum wells for the PSI scheme, mitigating the severe broadening effect for the excited states in GaN. To guide the fabrication of such devices, the doping effect on the peak gain has been analyzed. The two designs have demonstrated distinct doping density dependence and it is mainly attributed to the very different doping dependent broadening behaviors. The results reveal the possibility of GaN based THz-QCL lasing at room temperature.

Benefit of Pr3+ ions to the spectral properties of Er3+/Pr3+:SrLaAlO4 crystal for use in 2.7 μm mid-infrared laser

High optical quality Er3+ single doped and Er3+/Pr3+ co-doped SrLaAlO4 crystals were grown by the Czochralski method. Detailed spectroscopic analyses of Er3+:SrLaAlO4 and Er3+/Pr3+:SrLaAlO4 crystals were carried out. With the presence of Pr3+, the intensities of the red up-conversion and near-infrared emissions reduce to 1/4 and 1/10, while the intensity of mid-infrared emission increases to 1.6 times of those for Er3+:SrLaAlO4. Furthermore, the lifetimes of 4I11/2 upper and 4I13/2 lower laser levels for 2.7 μm emission fall from 1.06 ms to 4.42 ms–0.73 ms and 0.93 ms. It means that the self-termination bottleneck in Er3+ 2.7 μm laser was inhibited in a great degree. Deactivation effect of Pr3+ ions as well as the energy transfer mechanism in Er3+/Pr3+:SrLaAlO4 crystal are discussed in detail. The results indicate that the introduce of deactivation ion Pr3+ can be beneficial for achieving an enhanced 2.7 μm emission in Er3+/Pr3+:SrLaAlO4.