Research

In addition to teaching, the Faculty in the Department of Physics are actively engaged in the search for new knowledge and novel applications of physics. Researchers in the Department work in topics ranging from the very small (quantum systems) to the very large (space weather, astrophysics, and cosmology), from the highly theoretical (geometric algebra, many-body physics) to the very practical (photonics, vacuum physics technology, and instrumentation), and from pure hardcore physics (condensed matter physics, general relativity, and mathematical physics) to highly interdisciplinary topics (atmospheric physics, climate physics, and materials science). Listed below are the research groups in the Department:

Earth System Physics:
     •  Air Quality Group
               •  CambalizaLagrosasSimpas
     •  Physics of the Climate and Weather Group
               •  Estoque, Narisma, Olaguera, Villarin
     •  Geophysics Group
               •  Maquiling
     •  Space Weather Group
               •  Bennett, McNamara, Sugon

Materials Science:
     •  Auxetic Materials Group
               •  Chan
     •  Materials Characterization Group
               •  Chan
     •  Thin Films and Plasma Processing Group
               •  Culaba, Delos Santos, Jallorina, Mahinay

Photonics:
     •  Photonics Group
               •  Batiller, Cease, Guerrero, Indias

Physics Education:
     •  Physics Education Group
               •  Cambaliza, Chan, Culaba, Dailisan, Jallorina, Lagrosas, Maquiling

Theoretical and Computational Physics:
     •  Geometric Algebra Group
               •  McNamara, Sugon
     •  Gravitation Group
               •  Garcia

 
Some Selected Publications:

2015

Skew ray tracing in a step-index optical fiber using geometric algebra

By Sugon, Quirino Jr., McNamara, Daniel J., SJ

We used geometric algebra to compute the paths of skew rays in a cylindrical, step-index multimode optical fiber. To do this, we used the vector addition form for the law of propagation, the exponential of an imaginary vector form for the law of refraction, and the juxtaposed vector product form for the law of reflection. In particular, the exponential forms of the vector rotations enables us to take advantage of the addition or subtraction of exponential arguments of two rotated vectors in the derivation of the ray tracing invariants in cylindrical and spherical coordinates. We showed that the light rays inside the optical fiber trace a polygonal helical path characterized by three invariants that relate successive reflections inside the fiber: the ray path distance, the difference in axial distances, and the difference in the azimuthal angles. We also rederived the known generalized formula for the numerical aperture for skew rays, which simplifies to the standard form for meridional rays.

2012

Ray transfer matrix perturbation for an optical component with aberration

By

Jerry T. Barretto, Clark Kendrick C. Go, and Stein Alec C. Baluyot, "Ray transfer matrix perturbation for an optical component with aberration," Chin. Opt. Lett. 10, 080801- (2012)

The perturbation theory of matrices is applied to ray transfer matrices (RTMs) to describe an optical component with aberration. A quantitative description of the perturbation extent corresponding to aberration strength is provided using condition numbers and absolute errors for the perturbed RTM. An application to a single small aberration is presented, and the results are compared with those of the diffraction theory of aberrations.

OCIS codes: 080.0080, 080.2720, 080.2730.
doi: 10.3788/COL201210.080801.

Polarization ellipse and Stokes parameters in geometric algebra

By Sugon, Quirino Jr., McNamara, Daniel J., SJ

Adler G. Santos, Quirino M. Sugon, Jr., and Daniel J. McNamara, "Polarization ellipse and Stokes parameters in geometric algebra," J. Opt. Soc. Am. A 29, 89-98 (2012).

In this paper, we use geometric algebra to describe the polarization ellipse and Stokes parameters. We show that a solution to Maxwell’s equation is a product of a complex basis vector in Jackson and a linear combination of plane wave functions. We convert both the amplitudes and the wave function arguments from complex scalars to complex vectors. This conversion allows us to separate the electric field vector and the imaginary magnetic field vector, because exponentials of imaginary scalars convert vectors to imaginary vectors and vice versa, while exponentials of imaginary vectors only rotate the vector or imaginary vector they are multiplied to. We convert this expression for polarized light into two other representations: the Cartesian representation and the rotated ellipse representation. We compute the conversion relations among the representation parameters and their corresponding Stokes parameters. And finally, we propose a set of geometric relations between the electric and magnetic fields that satisfy an equation similar to the Poincaré sphere equation. © 2012 Optical Society of America

2011

Near- Surface Atmospheric Dynamics of Changing Crops to Forests in the Philippines

By Narisma, Gemma Teresa T.

Julie Mae B. Dado, Faye Abigail T. Cruz, and Gemma Teresa T. Narisma, “Near- Surface Atmospheric Dynamics of Changing Crops to Forests in the Philippines,” SPP 2011-171.

We explore the effects of changing cropland into forests on the energy and water balances and the consequent changes in near surface atmospheric conditions. We used two regional climate models, RegCM3 and MM5, to simulate a 10-year period using two land-cover scenarios. The first scenario represents current land cover while the second scenario replaces this current land cover with broadleaf trees. Results from both models show that changing cropland areas to forests results in an increase in temperature. This warming is due mainly to increased sensible heat flux with the change in albedo being the dominant factor.

(national conference)

Aerosol size distribution derived from 2010 New Year’s spectrometric data in Manila Observatory, Philippines

By Lagrosas, Nofel D.

Rafael Chu1*, Nofel Lagrosas1,2, “Aerosol size distribution derived from 2010 New Year’s spectrometric data in Manila Observatory, Philippines,” SPP 2011-174.

A parametric approach was used to compute the volume size distribution from aerosol optical depth values measurements during the 2010 New Year celebration. A fine mode (<0.1 um) was observed after midnight, corresponding to the onset of the firework activity. The appearance of a coarser mode (>0.1 um) at around 3am is attributed to high relative humidity values and low difference between ambient and dew point temperatures, both facilitating condensation and thus an increase in particulate radius.

(national conference)

“Evaluation of satellite-based rainfall estimates over the Philippines

By Narisma, Gemma Teresa T.

Carlo Jamandre1* and Gemma Narisma1, 2, “Evaluation of satellite-based rainfall estimates over the Philippines,” SPP 2011-165.  

This study aims to evaluate satellite-based rainfall for its use potential use within the Philippines. In this study, two satellite-based rainfall products, CMORPH and TRMM, are compared with observation from eight ground stations in the Philippines and the gridded rainfall dataset, APHRODITE. Results show that TRMM data gives slightly better estimates than CMORPH but both, in general, do not correlate well with observations. Rainfall estimates improve during the months of August to December and during days with extreme precipitation. The performance of satellite-derived rainfall products seems to be dependent on both geographical location and the amount of rainfall estimated.

Monitoring the Presence of Cu2O and CuO During Thermal Oxidation of Copper Thin Film via In Situ Measurement of Transmittance

By Culaba, Ivan B.

Jennifer T. Damasco Ty1, 2*, Marianne Lorene L. Macailing1, Ivan B. Culaba2 and Roland V. Sarmago1, “Monitoring the Presence of Cu2O and CuO During Thermal Oxidation of Copper Thin Film via In Situ Measurement of Transmittance,” SPP 2011-104.

The formation of Cu2O and CuO from thermally oxidizing a copper thin film deposited on a glass substrate is monitored by looking at the transmittance when a 633 nm laser light is incident on the copper thin film during oxidation. Transmittance increases initially and then plateaus for samples oxidized at a maximum temperature of 204°C, indicating the formation of Cu2O. Transmittance increases initially and then gradually declines for samples oxidized at a maximum temperature of 378°C, indicating the formation of CuO. The films have been characterized using SEM, EDX, and UV/Vis analysis.

(national conference)

Characterization of Ten-year TRMM Rainfall Measurements over the Philippines

By Lagrosas, Nofel D.

Cornelius Csar Jude H. Salinas1 and Nofel Lagrosas1,2, “Characterization of Ten-year TRMM Rainfall Measurements over the Philippines,” SPP 2011-176.

Ten-year precipitation data derived from the Tropical Rainfall Measuring Mission (TRMM) is presented in this paper. The utilization of TRMM 3B42 data provide a description of the rainfall/precipitation features of the Philippine archipelago (0N-20N, 110E-130E). The monthly spatio-temporal characteristics of rainfall in the Philippines are also presented. The results show spatial variation of dry and wet seasons in the Philippines.

(poster, national conference)