Depth of penetration of a 785nm wavelength laser in food powders

Kuanglin Chao; Sagar Dhakal; Jianwei Qin; Moon S. Kim; Yankun Peng; Walter F. Schmidt

doi:10.1117/12.2177000

13 May 2015 Depth of penetration of a 785nm wavelength laser in food powders

Kuanglin Chao, Sagar Dhakal, Jianwei Qin, Moon S. Kim, Yankun Peng, Walter F. Schmidt

Author Affiliations +

Proceedings Volume 9488, Sensing for Agriculture and Food Quality and Safety VII; 94880U (2015) https://doi.org/10.1117/12.2177000
Event: SPIE Sensing Technology + Applications, 2015, Baltimore, Maryland, United States

Abstract

Raman spectroscopy is a useful, rapid, and non-destructive method for both qualitative and quantitative evaluation of chemical composition. However it is important to measure the depth of penetration of the laser light to ensure that chemical particles at the very bottom of a sample volume is detected by Raman system. The aim of this study was to investigate the penetration depth of a 785nm laser (maximum power output 400mw) into three different food powders, namely dry milk powder, corn starch, and wheat flour. The food powders were layered in 5 depths between 1 and 5 mm overtop a Petri dish packed with melamine. Melamine was used as the subsurface reference material for measurement because melamine exhibits known and identifiable Raman spectral peaks. Analysis of the sample spectra for characteristics of melamine and characteristics of milk, starch and flour allowed determination of the effective penetration depth of the laser light in the samples. Three laser intensities (100, 200 and 300mw) were used to study the effect of laser intensity to depth of penetration. It was observed that 785nm laser source was able to easily penetrate through every point in all three food samples types at 1mm depth. However, the number of points that the laser could penetrate decreased with increasing depth of the food powder. ANOVA test was carried out to study the significant effect of laser intensity to depth of penetration. It was observed that laser intensity significantly influences the depth of penetration. The outcome of this study will be used in our next phase of study to detect different chemical contaminants in food powders and develop quantitative analysis models for detection of chemical contaminants.

Citation Download Citation

Kuanglin Chao, Kuanglin Chao, Sagar Dhakal, Sagar Dhakal, Jianwei Qin, Jianwei Qin, Moon S. Kim, Moon S. Kim, Yankun Peng, Yankun Peng, Walter F. Schmidt, Walter F. Schmidt, "Depth of penetration of a 785nm wavelength laser in food powders", Proc. SPIE 9488, Sensing for Agriculture and Food Quality and Safety VII, 94880U (13 May 2015); doi: 10.1117/12.2177000; https://doi.org/10.1117/12.2177000

ACCESS THE FULL ARTICLE

PERSONAL SIGN IN
Full access may be available with your subscription

Email or Username Forgot your username?

Password Forgot your password?

Show

Remember Email/Username on this computer

Remember Password

No SPIE account? Create an account
or Institutional Sign In via Shibboleth

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available

Members: $14.40

Non-members: $18.00 ADD TO CART

Show All Keywords

Keywords/Phrases

Search In:

Publication Years