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Low-‐cost op*cal sensor for fast and accurate determina*on of liquid mixtures in foods or beverages
Pablo Aitor Pos,go
E. Baquedano, L. Da Cruz Ins*tuto de Micro y Nanotecnologia, IMN -‐ CNM -‐ CSIC (CEI UAM+CSIC) Isaac
Newton, 8, E-‐28760, Tres Cantos, Madrid, Spain
pabloaitor.pos*[email protected]
Sensor characteris*cs
• Low-‐cost (can be disposable) • Op*cal (measures changes in refrac*ve index) • Fast (1 s) • Accurate (1.56x10−5 refrac*ve index units) • Determina*on of liquid mixtures in foods or beverages: alcohol in water, mixtures of oil, any different liquids…Examples: – Is this oil pure or has something else on it? – What is the % of 2 liquids mixtured in a beverage?
Absop,on of Light by nanopar,cles (plasmons)
Copa Lycurgus (Romano tardío, IV D.C)
Luz reflejada
Luz transmitida
1) Metallic Nanostructures 2) A “good” metal (Au, Ag…)
Anomalía de +: Transición de un orden evanescente a un orden de difracción propaga*vo en una red. Condición de Bragg:
4
Diseño y análisis numérico
Análisis de las propiedades óp*cas de una red de nanocintas de Au.
Nanocintas de Au 375 nm de ancho 750 nm periodo
λRA(vidrio)
λ = 1119 nm
λRA (superestrato)
λ = 748 nm
3λ/2 resonancia 3λ/2 resonancia
λ = 606 nm
λ = 773 nm
Vidrio o plas*co
Sello PDMS
Resina
1.0µm
Proceso de fabricación: litografia blanda
Sencillo, bajo coste, áreas grandes
Resultados: medida transmisión incidencia normal
1.0µm
7
Resultados
§ Superestrato: Glicerol 0%, 3%, 6%, 9%, 12%, 15%) § Lámpara halógena 100W § Lente2x apertura 0.06 § Fibra óp*ca 1 mm de diámetro § Espectrómetro portá*l Ocean Op*cs USB4000
Variación de intensidad espectral respecto al agua.
8
Resultados
Intervalo de integración de intensidad rela*va. 650 y 750 respec*vamente.
Número de longitudes de onda dentro del intervalo de integración
0.000 0.005 0.010 0.015 0.020 0.025
0.0
0.5
1.0
1.5
2.0
2.5
SR=10488,86 nm%/RIU
Datos obtenidos Ajuste lineal
Res
pues
ta in
tegr
ada,
R (x
102 n
m%
)
Cambio índice de refracción (x10-2)
0 250 500 750 1000 1250
0.0
0.5
1.0
1.5
2.0
2.51.355
1.351
1.346
1.341
1.331
Res
pues
ta in
tegr
ada,
R (x
102 n
m%
)
Tiempo (s)
1.337
Resolución de detección:
σ/SR= 1.56 x 10-‐5 Nivel de ruido
σ=0.16% x nm Área ac,va 0.75 mm de diámetro
N=200 τ=5ms -‐> Resolución temporal 1s
Performance of the sensor
• Very small volume for detec*on, 0.0025 mL • Spot of detec*on d=0.75 mm • In this small volume, it can detect a mass as small as 0,1 mg
• Or a volume as small as 8x10-‐5 mL. • The detec*on can be as fast as 1 second. • It can be used with a smartphone if an specific but simple device is aXached and specific soYware is used
1 cm
Conclusions • We present a new way of easy, op*cal detec*on using a nanophotonic
sensor. • Applica*ons can be from detec*on of the quality of food (virgin or
mixed olive oil, wine or beers…) quality of pure or mixed alcohols, gasoline, etc. to iden*fica*on of specific labeling and security.
• The nanophotonic sensor only needs a very small volume for detec*on of 0.0025 mL and can detect a mass as small as 0,1 mg or a volume as small as 8x10-‐5 mL. The detec*on can be as fast as 1 second.
• The sensor can be coupled to a smartphone for an easy detec*on of the
proper*es of the substance.
• It can be used in an easy way with a smartphone with home-‐made MYSA App
E. Baquedano, M. U. González, R. Paniagua-‐Domínguez, J. A. Sánchez-‐Gil, and P. A. Pos*go, "Low-‐cost and large-‐size nanoplasmonic sensor based on Fano resonances with fast response and high sensi*vity," Opt. Express 25, 15967-‐15976 (2017)