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Acoustic properties are the main criteria to evaluate the compatibility of tested materials as a medical phantom. We determined the acoustic properties of konjac glucomannan (KGM) gel to verify its compatibility as a medical phantom. The acoustic properties measurement employed ultrasonic insertion technique and utilized two identical transducers of 5 MHz center frequencies. One KGM gel block with 5.62 mm thickness was used as sample to determine its longitudinal speed, acoustic impedance and attenuation coefficient at three different water temperatures; (21.5 ± 0.1), (22.5 ± 0.1) and (23.5 ± 0.1) °C. Findings indicated that its longitudinal speed and acoustic impedance increased from (1495 ± 1) to (1499 ± 1) m s-1 and (1.555 ± 0.001) to (1.559 ± 0.001) × 106 kg m-2 s-1 as the water temperature increased from (21.5 ± 0.1) to (23.5 ± 0.1) °C. It also indicated that its attenuation coefficient varied around (0.1303 ± 0.0107) to (0.1373 ± 0.0103) dB cm-1 with increasing water temperature. KGM gel is compatible to be a medical phantom since its acoustic properties are comparable to the acoustic properties of human soft tissue.

Achieving tuneable photoluminescence via controlled co-doping of rare earth ions in lithium niobate based glasses are challenging. A series of Er3+/ Nd3+ co-doped tellurite glasses of composition (70-x-y) TeO2 – 15 Li2CO3 – 15 Nb2O5 – (x) Er2O3 – (y) Nd2O3 with x = 0; 1.0 mol % and 0 ≤ y ≤ 1.0 mol % are prepared using melt quenching technique. The influence of co-dopants on the emission properties is analyzed and discussed using partial energy level diagram of rare earth ions. The dopants concentration dependent physical properties such as refractive index, molar volume, density, polarizability and molar refractions are determined. The down-converted luminescence spectra for 2G9/2 à4I9/2 transition reveal a strong green emission band centred at 497 nm is attributed to the energy transfer from erbium to neodymium ion. The emission spectra exhibit five prominent peaks centred at 497, 539, 553, 616 and 634 nm corresponding to the transitions from 2H11/2, 4S3/2 and 4F9/2 excited states to the ground state of Er3+ ion and the transitions from 2G9/2, 2G7/2, 2H11/2 and 4F9/2 excited states to ground state of Nd3+ ion. The highest intensity is achieved for x = y = 1.0 mol%. The excellent luminescence response suggests that our glasses may be nominated for solid state lasers and other photonic applications.

Although Nd:YAG was invented in the 1960s in the last century, it has been and still the most commonly crystal material widely used in all types of solid-state lasers systems such as frequency-doubled continuous wave, high-energy Q-switched, and so forth in applications to the medical, industrial, military and scientific research. A Crystal Growth System namely Automatic Diameter Control -Crystal Growth System (ADC-CGS) was utilized to prepare a single crystal of Nd:YAG grown in the <111> direction using the Czochralski. By an effective control on the growth parameter such as maintaining temperature gradient by controlling the output power and the growth rate, an Nd:YAG single crystal with the dimensions of 75 mm in length and 30 mm in diameter was successfully produced using the ADC-CGS. The color of the Nd:YAG single crystal is slightly purple when exposed to the light. This is a unique characteristic of YAG crystal when doped with Neodymium (Nd) followed by a better fluorescence lifetime and thermal conductivity.

Modifying the optical properties of rare earth doped phosphate glasses in a tunable fashion via the embedment of magnetic nanoparticles (NPs) is challenging for magneto-optic devices. Glasses with compositions (69-x)P2O5-30ZnO-1Er2O3-(x)Fe3O4, where x = 0 to 1.5 mol% are prepared by conventional melt quenching method. The Fe3O4NPs concentration dependent density, molar volume, refractive index and optical properties are determined. Density and molar volume shows strong correlation with structural alteration in the presence of NPs. The XRD spectra confirm the disordered nature of the glass and TEM micrograph display the presence of spherical NPs with average size ~26 nm. The optical band gap and Urbach energy calculated from the room temperature absorption spectra recorded in the range of 350-1700 nm reveal significant improvement. The density and refractive index increases and the molar volume decreases with the increase of Fe3O4contents. The energy band gap for direct and indirect transitions varies in the range of 4.47-3.64 eV and 4.27-3.53 eV, respectively. The Urbach energy increases from 0.15 to 0.19 eV as the NPs concentration increases from 0 to 1.5 mol%.